there have been a couple of bug fixes after the formal 5.4.0 release but afaik not in the virtual machine code (which normally is the most sensitive); i used to mark low level changes so that it got signaled (in context) but the byte code version info changed late in 5.4 dev so i no longer do that now
although i occasionally have run into buglets in 5.4 code - which to me is quite natural as it concerns dev / exp versions so one gets what one downloads, i.e. one can only blame oneself for using such versions and hardly complain - lua is quite stable and reliable (given the massive amount of lua code that we use in context) ... so, normally patience - read: wait for updates - is the answer
Oh I see, I wasn't aware that the dev versions are used. After recompiling with the latest development code the error is gone. One other question about LuaMetaTeX 2.7.1: I noticed that the terminal_input callback is gone. Does this mean that the current behaviour of basically freezing when previously terminal input was requested is hardcoded or is some other callback invoked which can then provide some tokens? Marcel