Since installing v2.33 the following doesn't always work to remove a tag. This worked fine prior to 2.33.
Format value "TAG": $if(1,,)
I use this is on "temporary" tags that I create as part of a mult-action action. For instance:
Format value "TMP_ARTISTSORT": %artist%
Format value "TMP_ARTISTSORT": $if(1,,)
I've also tried using the "Remove fields" action to do this, but this too does not seem to work in removing the temporary tags.