This handles the problem, thanks.

Yes, that is correct.

That's weird, I can reproduce it with a fresh pull from dev.gnupg.org (I can't clone it because it keeps giving me an error like "no rule to make target audit-events.h) by configuring with CFLAGS set to -fsantize=address -ldl and LDFLAGS set to -lasan. I added the -ldl because of a linking error with symbol dlsym (only when -fsantize=address is present). It more specifically complains about a READ access of size 1 and heap-buffer-overflow on address 0xb30037b0. It also mentions that this address is a wild pointer. The call tree looks as follows:
iobuf_temp_with_content
keybox_get_keyblock
keydb_get_keyblock
do_export_stream
do_export
export_pubkeys
main

Great, thanks for the quick response!