diff --git a/R/reconcileAnnotationBoundaries.R b/R/reconcileAnnotationBoundaries.R
index 322e4ff..8759bb2 100755
--- a/R/reconcileAnnotationBoundaries.R
+++ b/R/reconcileAnnotationBoundaries.R
@@ -193,7 +193,7 @@
                 naNames <- names(which(is.na(resListUpdate)))
                 for (changeName in naNames) {
                     modVals <- gateList[[changeName]][[channel]]
-                    if (!is.na(modVals)) {
+                    if (any(!is.na(modVals))) {
                         #there is empirical data for an experimental unit, so attempt to use it.
                         #this can arise if the "Preference" setting of supervision leads to using
                         #a gateNumber that is absent from a level of the imputation hierarchy.
diff --git a/vignettes/faustPFDA.Rmd b/vignettes/faustPFDA.Rmd
index 473643b..9437050 100644
--- a/vignettes/faustPFDA.Rmd
+++ b/vignettes/faustPFDA.Rmd
@@ -12,7 +12,8 @@ vignette: >
 ```{r setup, include = FALSE}
 knitr::opts_chunk$set(
   comment = "#>",
-  dpi = 300
+  dpi = 300,
+  error = TRUE
 )
 ```