Crashing when opening MusicXML files

MuseScore 1.3 imports it, 2.3.2, 3.5.2 and 3.6.2 and the lates 3.x development build crash on it And on Windows (too).
XML export stems from Guitar Pro 7.5.5 and claims to be MusicXML 2.0, which is quite old, we're at 3.1 meanwhile.

Stack trace:

1 Ms::Measure::getSegment measure.h 207 0xf1219b
2 Ms::addElemOffset importmxmlpass2.cpp 857 0x8a4a86
3 Ms::MusicXMLParserNotations::addToScore importmxmlpass2.cpp 6293 0x8c8a20
4 Ms::MusicXMLParserPass2::note importmxmlpass2.cpp 4612 0x8bb0aa
5 Ms::MusicXMLParserPass2::measure importmxmlpass2.cpp 2022 0x8aa6ed
6 Ms::MusicXMLParserPass2::part importmxmlpass2.cpp 1682 0x8a8dfc
7 Ms::MusicXMLParserPass2::scorePartwise importmxmlpass2.cpp 1571 0x8a829a
8 Ms::MusicXMLParserPass2::parse importmxmlpass2.cpp 1540 0x8a80ba
9 Ms::MusicXMLParserPass2::parse importmxmlpass2.cpp 1521 0x8a803d
10 Ms::importMusicXMLfromBuffer importmxml.cpp 57 0x88c458
11 Ms::doValidateAndImport importxml.cpp 235 0x7b03a4
12 Ms::importMusicXml importxml.cpp 281 0x7b072c
13 Ms::readScore file.cpp 2352 0x4cb0f0
14 Ms::MuseScore::readScore file.cpp 473 0x4bbfcc
15 Ms::MuseScore::openScore file.cpp 415 0x4bba8c
16 Ms::MuseScore::doLoadFiles file.cpp 348 0x4bb1d3
17 Ms::MuseScore::openFiles file.cpp 313 0x4bae1c
18 Ms::MuseScore::cmd musescore.cpp 6241 0x4312c3
19 Ms::MuseScore::cmd musescore.cpp 6033 0x4301f2
20 Ms::MuseScore::qt_static_metacall moc_musescore.cpp 524 0x5ebc8c
...

Avoiding that crash by some band-aid code (checking whether measure is NULL before dereferencing it) gets me further, but reports corruptions:
Measure 12, Staff 1 incomplete. Expected: 31/32; Found: 16/16
Measure 27, Staff 1 incomplete. Expected: 31/32; Found: 16/16
Measure 33, Staff 1 incomplete. Expected: 15/16; Found: 16/16
Measure 36, Staff 1 incomplete. Expected: 31/32; Found: 16/16
Ignoring that resulted in the attached score

See https://github.com/musescore/MuseScore/pull/7602 (for 3.x)
And https://github.com/musescore/MuseScore/pull/7603 (for master, merged)