[3.1.2→3.2.0] Data conversion fails

[AMDmi3]

Describe the bug
After updating stratagus/wargus from 3.1.2 to 3.2.0, running wargus says that it can covert data inplace, but that fails. Removing data.Wargus and converting it from original game data works fine.

Screenshots and Logs

Running extractor as wartool -v -r '/home/marakasov/.stratagus/data.Wargus' '/home/marakasov/.stratagus/data.Wargus'
Extracting from expansion subdir
an error occurred trying to extract from the expansion archives
Supported sound decoders: WAVE AIFF VOC MOD MID OGG OPUS MP3 FLAC
Supported music decoders: CMD WAVE FLAC OGG OPUS MPG123 MODPLUG TIMIDITY MOD MIDI MP3
Can't open file 'scripts/wc2-config.lua': No such file or directory
[string "/home/marakasov/.stratagus/data.Wargus/scri..."]:121: attempt to concatenate field 'music_extension' (a nil value)
stack traceback:
	[string "/home/marakasov/.stratagus/data.Wargus/scri..."]:121: in main chunk

Desktop (please complete the following information):

• OS: FreeBSD
• Version 3.2.0