Mysterious export_TextGridCollection() error when exporting levels with inherited time information

[rpuggaardrode]

I was trying to export an emuDB to TextGrid collection. The db has an annotation superlevel word which inherits its time information from sublevel phone. I get the following error:

Error in if (min(slTier$start) > 0) { : missing value where TRUE/FALSE needed

I gather that this originates from line 185 in export_TextGridCollection() where the tier is padded with an interval starting at 0 if there isn't one already, but (presumably) if(min(slTier$start) > 0) fails because min(slTier$start > 0) returns NULL for some reason. This happens at 8% progress in my case, so most files are fine. Unfortunately I can't provide a reprex, the error is not very informative so I can't figure out which bundle is the culprit without some lengthy trial & error. Maybe a first solution would be to return an error message specifying the bundle & annotation level which causes the error?