Unexpected KoBoCAT error 400 file uploaded

Hello all!
I’ve checked the relevant and constraint columns many times and no question referring to itself, so what could be the problem here?

b’{“detail”:“ODK Validate Errors:\n>> Something broke the parser. See above for a hint.\norg.javarosa.xpath.XPathUnsupportedException: XPath evaluation: unsupported construct [filter expression]\n\nThe following files failed validation:\n${tmp_o2bh_01}\n\nResult: Invalid”}'training_tool.xlsx (51.4 KB)

Hello @musto,
I think it is a syntax error in the relevant clause in line 205
${u5a_second} != ‘98’ and ${u5a_second} != ‘99’ ${u5a_first} != ‘98’ and ${u5a_first} != ‘99’
There is probably an … and … missing (after the first ‘99’)

Might be interesting that the syntax problem is NOT detected by the Online validator.