Comment (by Roland Haas):

Even reverting everything to ET_2019_10 and using the ET_2019_10 thornlist did not fix this. Next will be a fresh ET_2019_10 checkout though I suspect that one may have to live with this.

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Ticket URL: https://bitbucket.org/einsteintoolkit/tickets/issues/2345/infinite-make-loop-building-on-blue-waters