Booklet layout 2UP is not working with lmtx for me.

MWE: under mkiv I get all 4 booklet pages laid out for two-sided print and fold.

\setuppapersize[A5][A4,landscape]
\setuparranging[2UP,doublesided]
\starttext
\dorecurse{4}{\input tufte \blank}
\dorecurse{3}{\input bryson \blank}
\dorecurse{3}{\input ward \blank}
\stoptext

context —version:
mtx-context     | main context file: /users/kitz/ctxmkiv/tex/texmf-context/tex/context/base/mkiv/context.mkiv
mtx-context     | current version: 2019.04.25 10:36




MNWE: When I switch to lmtx, only booklet pages 1 and 4 are set and repeated on next page.

context —version:
mtx-context     | main context file: /users/kitz/lmtx/tex/texmf-context/tex/context/base/mkiv/context.mkxl
mtx-context     | current version: 2019.08.17 12:16

There seems to be flushing of pages going on under lmtx. Thanks for any help.

Kitz