diff --git a/NEWS.md b/NEWS.md
index f83b34cf6adf4102b044843df6db0bccbbb455de..025519f7b365a1f180655e23a7b3a438809ba0b9 100644
--- a/NEWS.md
+++ b/NEWS.md
@@ -1,6 +1,7 @@
 # CSIndicators 1.1.2 (Release date: 2025-03-27)
 
 ### Fixes
+- Avoid using 'builtin' type functions in call to multiApply::Apply()
 - CST_PeriodStandardization: Set na.rm = TRUE when replacing infinite values with maximum/minimum period values
 - CST_PeriodPET(): Add longname and other variable metadata 
 - Not drop singleton time dimensions in 
diff --git a/R/MergeRefToExp.R b/R/MergeRefToExp.R
index 6d9fd6e88104d58c871254ac52171b4e4fce115d..69f722b7934de0df3185b4042304bd832946dc84 100644
--- a/R/MergeRefToExp.R
+++ b/R/MergeRefToExp.R
@@ -184,8 +184,10 @@ CST_MergeRefToExp <- function(data1, data2, start1 = NULL, end1 = NULL,
       names(dim(dates2)) <- time_dim
     }
   }
-  res <- Apply(list(dates1, dates2), target_dims = time_dim,
-               'c', output_dims = time_dim, ncores = ncores)$output1
+  res <- Apply(list(dates1, dates2),
+               target_dims = time_dim,
+               fun = function(x, ...) {c(x, ...)},
+               output_dims = time_dim, ncores = ncores)$output1
 
   if (inherits(dates1, 'Date')) {
     data1$attrs$Dates <- as.Date(res, origin = '1970-01-01')
@@ -421,7 +423,8 @@ MergeRefToExp <- function(data1, data2, dates1 = NULL, dates2 = NULL,
     }
   }
 
-  data1 <- Apply(list(data1, data2), target_dims = time_dim, fun = 'c',
+  data1 <- Apply(list(data1, data2), target_dims = time_dim,
+                 fun = function(x, ...) {c(x, ...)},
                  output_dims = time_dim, ncores = ncores)$output1
 
   if (all(names(dim(data1)) %in% data1dims)) {
diff --git a/R/PeriodAccumulation.R b/R/PeriodAccumulation.R
index 424a1c86b44a57be3cb88045a041b46991bc8417..2adf45f78da157b89aecaa4978a4f3090e2e9de4 100644
--- a/R/PeriodAccumulation.R
+++ b/R/PeriodAccumulation.R
@@ -274,7 +274,7 @@ PeriodAccumulation <- function(data, dates = NULL, start = NULL, end = NULL,
 
   if (is.null(rollwidth)) {
     # period accumulation
-    total <- Apply(list(data), target_dims = time_dim, fun = sum,
+    total <- Apply(list(data), target_dims = time_dim, fun = function(...) {sum(...)},
                    na.rm = na.rm, ncores = ncores)$output1
   } else {
     # rolling accumulation
@@ -338,7 +338,9 @@ PeriodAccumulation <- function(data, dates = NULL, start = NULL, end = NULL,
     }
   }
 
-  data_accum <- rollapply(data = data_vector, width = rollwidth, FUN = sum, na.rm = na.rm)
+  data_accum <- rollapply(data = data_vector, width = rollwidth,
+                          FUN = function(...) {sum(...)},
+                          na.rm = na.rm)
   if (!forwardroll) {
     data_accum <- c(rep(NA, rollwidth-1), data_accum) 
   } else {
diff --git a/R/PeriodMax.R b/R/PeriodMax.R
index b028d1014bbf119a415703d9f184ecf0ef85a738..46f09846517677865317337b5dce9beb6415df52 100644
--- a/R/PeriodMax.R
+++ b/R/PeriodMax.R
@@ -206,11 +206,10 @@ PeriodMax <- function(data, dates = NULL, start = NULL, end = NULL,
       }
     }
   }
-  total <- Apply(list(data), target_dims = time_dim, fun = max,
+  total <- Apply(list(data), target_dims = time_dim, fun = function(...) {max(...)},
                  na.rm = na.rm, ncores = ncores)$output1
   
   dim(total) <- c(dim(total), setNames(1, time_dim))
   return(total)
 }
 
-
diff --git a/R/PeriodMin.R b/R/PeriodMin.R
index a9be2d5436cb30e67edd87e9eb13ef3e8ce8caac..52fb10a91cef7d805d3ff0ac0863e07d6e35b2f9 100644
--- a/R/PeriodMin.R
+++ b/R/PeriodMin.R
@@ -206,7 +206,8 @@ PeriodMin <- function(data, dates = NULL, start = NULL, end = NULL,
       }
     }
   }
-  total <- Apply(list(data), target_dims = time_dim, fun = min,
+  total <- Apply(list(data), target_dims = time_dim,
+                 fun = function(...) {min(...)},
                  na.rm = na.rm, ncores = ncores)$output1
   dim(total) <- c(dim(total), setNames(1, time_dim))
   return(total)
diff --git a/R/SelectPeriodOnData.R b/R/SelectPeriodOnData.R
index 1cc2792ed9a1bb3cdd909fd99a4a1a1db6402559..731abb5c47320617b81e9b4816acf9b776708c78 100644
--- a/R/SelectPeriodOnData.R
+++ b/R/SelectPeriodOnData.R
@@ -121,7 +121,7 @@ SelectPeriodOnData <- function(data, dates, start, end,
                ncores = ncores)$output1
   # when 29Feb is included the length of the output changes:
   regular <- Apply(list(res), target_dims = time_dim,
-                   fun = sum, ncores = ncores)$output1
+                   fun = function(...) {sum(...)}, ncores = ncores)$output1
   dims <- dim(data)
   dims[names(dims) == time_dim] <- max(regular)
   if (any(regular != max(regular))) {
diff --git a/R/SelectPeriodOnDates.R b/R/SelectPeriodOnDates.R
index 550aad94ff28525af253b13a68b80d785f10725f..b95c50912c7f7cacb7b26051957bdb9083dec03b 100644
--- a/R/SelectPeriodOnDates.R
+++ b/R/SelectPeriodOnDates.R
@@ -53,7 +53,7 @@ SelectPeriodOnDates <- function(dates, start, end,
   }
   # when 29Feb is included the length of the output changes:
   regular <- Apply(list(res), target_dims = time_dim,
-                   fun = sum, ncores = ncores)$output1
+                   fun = function(...) {sum(...)}, ncores = ncores)$output1
   dims <- dim(dates)
   dims[names(dims) == time_dim] <- max(regular)
   if (any(regular != max(regular))) {