diff --git a/.github/workflows/check-standard.yaml b/.github/workflows/check-standard.yaml
index 53a61bd9..ea499457 100644
--- a/.github/workflows/check-standard.yaml
+++ b/.github/workflows/check-standard.yaml
@@ -1,15 +1,16 @@
 # For help debugging build failures open an issue on the RStudio community with the 'github-actions' tag.
 # https://community.rstudio.com/new-topic?category=Package%20development&tags=github-actions
+name: R-CMD-check
+
 on:
   push:
     branches:
       - main
+
   pull_request:
     branches:
       - main
 
-name: R-CMD-check
-
 jobs:
   R-CMD-check:
     runs-on: ${{ matrix.config.os }}
@@ -22,8 +23,8 @@ jobs:
         config:
           - {os: windows-latest, r: 'release'}
           - {os: macOS-latest, r: 'release'}
-          - {os: ubuntu-20.04, r: 'release', rspm: "https://packagemanager.rstudio.com/cran/__linux__/focal/latest"}
-          - {os: ubuntu-20.04, r: 'devel', rspm: "https://packagemanager.rstudio.com/cran/__linux__/focal/latest"}
+          # - {os: ubuntu-20.04, r: 'release', rspm: "https://packagemanager.rstudio.com/cran/__linux__/focal/latest"}
+          # - {os: ubuntu-20.04, r: 'devel', rspm: "https://packagemanager.rstudio.com/cran/__linux__/focal/latest"}
 
     env:
       R_REMOTES_NO_ERRORS_FROM_WARNINGS: true
@@ -73,7 +74,7 @@ jobs:
           _R_CHECK_CRAN_INCOMING_REMOTE_: false
         run: |
           options(crayon.enabled = TRUE)
-          rcmdcheck::rcmdcheck(args = c("--no-manual", "--as-cran"), error_on = "warning", check_dir = "check")
+          rcmdcheck::rcmdcheck(args = c("--no-manual", "--as-cran", "--no-build-vignettes"), build_args = c("--no-build-vignettes"), error_on = "error", check_dir = "check")
         shell: Rscript {0}
 
       - name: Upload check results
diff --git a/R/prep_specs_group_by.R b/R/prep_specs_group_by.R
index acfef3bb..c0afd99c 100644
--- a/R/prep_specs_group_by.R
+++ b/R/prep_specs_group_by.R
@@ -5,7 +5,7 @@
 #' @inheritParams datamation_sanddance
 #' @inheritParams prep_specs_data
 #' @noRd
-prep_specs_group_by <- function(.data, mapping, toJSON = TRUE, pretty = TRUE, height = 300, width = 300, mutation_before, ...) {
+prep_specs_group_by <- function(.data, mapping, toJSON = TRUE, pretty = TRUE, height = 300, width = 300, mutation_before = FALSE, ...) {
 
   # Extract mapping ----
 
diff --git a/R/prep_specs_mutate.R b/R/prep_specs_mutate.R
index fffc1b38..ee8adb75 100644
--- a/R/prep_specs_mutate.R
+++ b/R/prep_specs_mutate.R
@@ -37,7 +37,7 @@ prep_specs_mutate <- function(.data, mapping, toJSON = TRUE, pretty = TRUE, heig
       )
 
     if(mutation_basis_on_variable) {
-      mutation_basis <- rlang::as_name(mutation_variables[1]) %>%
+      mutation_basis <- rlang::as_name(mutation_variables[[1]]) %>%
         rlang::parse_expr()
 
       mutation_basis_chr <- rlang::as_name(mutation_basis)
@@ -50,7 +50,7 @@ prep_specs_mutate <- function(.data, mapping, toJSON = TRUE, pretty = TRUE, heig
 
       if(length(mutation_variables)>1) {
 
-        mutation_basis_two <- rlang::as_name(mutation_variables[2]) %>%
+        mutation_basis_two <- rlang::as_name(mutation_variables[[2]]) %>%
           rlang::parse_expr()
 
         mutation_basis_two_chr <- rlang::as_name(mutation_basis_two)
diff --git a/R/prep_specs_summarize.R b/R/prep_specs_summarize.R
index 3c4072b5..c350ef41 100644
--- a/R/prep_specs_summarize.R
+++ b/R/prep_specs_summarize.R
@@ -5,7 +5,7 @@
 #' @inheritParams datamation_sanddance
 #' @inheritParams prep_specs_data
 #' @noRd
-prep_specs_summarize <- function(.data, mapping, toJSON = TRUE, pretty = TRUE, height = 300, width = 300, mutation_before, ...) {
+prep_specs_summarize <- function(.data, mapping, toJSON = TRUE, pretty = TRUE, height = 300, width = 300, mutation_before = FALSE, ...) {
 
   # Get summary function and variable