deriving track languages doesn't work due to the regex becoming too large
The default in new installations is to have all languages enabled for deriving the track language. Combined with issue #3047 (closed) this means that more than 7.000 languages are enabled by default. The resulting regular expression will then be around 100 KB in size.
Unfortunately the PCRE library used by
QRegularExpression only uses two-byte integers for string offsets, which limits the maximum size of a regular expression to around 2^(2*8)- 1 = 65.535 bytes.