Exhaustive testing of indexing Bible modules - results with BD 1.6 (latest nightly build)

I have begun exhaustively testing every Bible module to see whether it can be indexed for searching.
Though the majority of modules can be indexed successfully, there are still many that cannot.

Of those that cannot, most fail at 0% of the progress indicator, but there are some that get beyond that and still fail.
Here are the results so far, listing only those that failed, and for now at least, omitting the beta modules from Wycliffe, which are still to be tested.
I have not distinguished which repository the module was installed from.

Fail at 0% :
ASV, BWE, Chamorro, Common, Darby, FinPR, FreCrl, FreLSG, GerSch, ItaDio, ItaRive, JPS, LO, Maori, Montgomery, OrthJBC, PL_BW1997, RNKJV, RST, RWebster, RusVzh, SpaSEV, Swahili, TischMorph, Uma, Vulgate, Weymouth, Xhosa, YLT.

Fail at > 0% of progress :
2TGreek 70%
Murdock 12%
PolBybTysia 4%
Swe1917 2%
SweFB1998 49%

These non-zero results might be a good clue to the root cause.

– David Haslam