I cannot get a PDF/A document produced with the latest MkIV beta 2020.05.18 16:46 (LMTX works without issue). Using the example from the wiki (https://wiki.contextgarden.net/PDF/A) I get the error stating:
<inserted text> ... \p_file {\backendparameter {xmpfile}}\ifempty
\p_file \else \clf_setxmpf...
\setup_backend ...end [#1]\the \everysetupbackend
l.11 ...ISO coated v2 300\letterpercent\space (ECI)]
mtx-context | fatal error: return code: 1
Removing either of the \setupbackend instructions still results in the same error.
Same issue for PDF/X.
Is it a bug, or is it me?