diff --git a/R/add_biodiversity.R b/R/add_biodiversity.R
index 22479b97..73465409 100644
--- a/R/add_biodiversity.R
+++ b/R/add_biodiversity.R
@@ -282,7 +282,7 @@ methods::setMethod(
 
     # Finally set the data to the BiodiversityDistribution object
     y <- x$clone(deep = TRUE)
-    x$set_biodiversity(id, bd)
+    y$set_biodiversity(id, bd)
   }
 )
 
@@ -475,7 +475,7 @@ methods::setMethod(
 
       # Finally set the data to the BiodiversityDistribution object
       y <- x$clone(deep = TRUE)
-      x$set_biodiversity(id, bd)
+      y$set_biodiversity(id, bd)
     }
   }
 )
@@ -696,7 +696,7 @@ methods::setMethod(
 
       # Finally set the data to the BiodiversityDistribution object
       y <- x$clone(deep = TRUE)
-      x$set_biodiversity(id, bd)
+      y$set_biodiversity(id, bd)
     }
   }
 )
diff --git a/R/write_output.R b/R/write_output.R
index 13682d8c..9555e630 100644
--- a/R/write_output.R
+++ b/R/write_output.R
@@ -57,7 +57,7 @@ methods::setMethod(
 
     # This function will only capture the distribution model object and will
     # save them separately
-    if(any(class(mod) %in% getOption("ibis.engines")) ){
+    if(any(mod$get_name() %in% getOption("ibis.engines")) ){
       # FIXME: If errors occur, check harmonization of saving among engines.
       mod$save(fname = fname)
     } else if(is.Raster(mod)){
@@ -374,7 +374,7 @@ methods::setMethod(
       # Model parameters in a tibble
       output[["params"]][["id"]] <- as.character(model$id)
       output[["params"]][["runname"]] <- as.character(model$runname)
-      output[["params"]][["algorithm"]] <- class(mod)[1]
+      output[["params"]][["algorithm"]] <- mod$get_name()
       output[["params"]][["equation"]] <- mod$get_equation()
       # Collect settings and parameters if existing
       if( !is.Waiver(mod$get_data("params")) ){
@@ -420,7 +420,7 @@ methods::setMethod(
       # Model parameters in a tibble
       output[["params"]][["id"]] <- as.character(mod$modelid)
       output[["params"]][["runname"]] <- as.character(model$model$runname)
-      output[["params"]][["algorithm"]] <- class(model)[1]
+      output[["params"]][["algorithm"]] <- mod$get_name()
       if( "settings" %in% names(mod) ){
         output[["params"]][["settings"]] <- model$settings$data
       }
@@ -715,31 +715,28 @@ methods::setMethod(
       !is.Waiver(mod$get_data("fit_best"))
     )
 
-    # FIXME MH: Class of mod is only R6 and DistributionModel currently but no engine
-    warning("Due to a bug, there is no check if the object has a valid engine.",
-            call. = FALSE)
-    # # Check that model type is known
-    # assertthat::assert_that( any(sapply(class(mod), function(z) z %in% getOption("ibis.engines"))) )
-    # # Depending on engine, check package and load them
-    #
-    # if(inherits(mod, "GDB-Model")){
-    #   check_package("mboost")
-    # } else if(inherits(mod, "BART-Model")){
-    #   check_package("dbarts")
-    # } else if(inherits(mod, "INLABRU-Model")){
-    #   check_package("INLA")
-    #   check_package("inlabru")
-    # } else if(inherits(mod, "BREG-Model")){
-    #   check_package("BoomSpikeSlab")
-    # } else if(inherits(mod, "GLMNET-Model")){
-    #   check_package("glmnet")
-    #   check_package("glmnetUtils")
-    # } else if(inherits(mod, "STAN-Model")){
-    #   check_package("rstan")
-    #   check_package("cmdstanr")
-    # } else if(inherits(mod, "XGBOOST-Model")){
-    #   check_package("xgboost")
-    # }
+    # Check that model type is known
+    assertthat::assert_that( any(sapply(mod$get_name(), function(z) z %in% getOption("ibis.engines"))) )
+
+    # Depending on engine, check package and load them
+    if(mod$get_name() == "GDB-Model"){
+      check_package("mboost")
+    } else if(mod$get_name() == "BART-Model"){
+      check_package("dbarts")
+    } else if(mod$get_name() == "INLABRU-Model"){
+      check_package("INLA")
+      check_package("inlabru")
+    } else if(mod$get_name() == "BREG-Model"){
+      check_package("BoomSpikeSlab")
+    } else if(mod$get_name() == "GLMNET-Model"){
+      check_package("glmnet")
+      check_package("glmnetUtils")
+    } else if(mod$get_name() == "STAN-Model"){
+      check_package("rstan")
+      check_package("cmdstanr")
+    } else if(mod$get_name() == "XGBOOST-Model"){
+      check_package("xgboost")
+    }
 
     # --- #
     # Return the model
diff --git a/tests/testthat/test_objectinheritance.R b/tests/testthat/test_objectinheritance.R
index a8188033..3238aa61 100644
--- a/tests/testthat/test_objectinheritance.R
+++ b/tests/testthat/test_objectinheritance.R
@@ -36,6 +36,11 @@ test_that('Check that distribution objects are properly inherited', {
     add_biodiversity_polpo(virtual_range, field_occurrence = 'Observed', name = 'Virtual points')
   expect_equal(x$biodiversity$length(),0)
 
+  # For Poipa
+  pa <- virtual_points |> add_pseudoabsence(field_occurrence = "Observed",template = background)
+  x |> add_biodiversity_poipa(pa, field_occurrence = "Observed",docheck = FALSE)
+  expect_equal(x$biodiversity$length(),0)
+
   # Offsets
   suppressMessages( suppressWarnings( x |> add_offset_range(virtual_range) ) )
   expect_s3_class(x$offset, "Waiver")
@@ -49,6 +54,13 @@ test_that('Check that distribution objects are properly inherited', {
   expect_length(x$get_predictor_names(), 0)
   expect_length(y$get_predictor_names(), 14)
 
+  # Remove a predictor
+  y |> rm_predictors("ndvi_mean_50km")
+  expect_length(y$get_predictor_names(), 14)
+  y <- y |> rm_predictors("ndvi_mean_50km")
+  expect_length(y$get_predictor_names(), 13)
+  expect_error(y |> rm_predictors("ndvi_mean_50km")) # Trying to remove it again should lead to an error
+
   # Add elevation
   y <- x |> add_predictor_elevationpref(predictors$elevation_mean_50km, 500, 1000)
   expect_length(y$get_predictor_names(), 2)