Hello!
Chapter ISSUES WITH MULTI-SEGMENT MATCHING of pcre2partial.html includes item 2 with description how to process with lookbehind assertions.
I think it's important to add to this algorithm a some words about "no match": If result of partial match is "no match" then last max_lookbehind characters of subject string must be keeped to next matching too. Matching of next segment must start with appropriate offset.
Thanks. --## List details at https://lists.exim.org/mailman/listinfo/pcre-dev
