meta is an Inform 7 flag explained in the WorldModelKit. From giving that page a quick read, I think the issue is that I6 verbs are marked as meta/out-of-world, whereas for I7 it is the action that matters. While they usually match up, sometimes they don’t. (I6 only gained the option to specify meta actions differently from verbs in August this year!) So “understand as a mistake” needs to be marked as an I7 meta action even while the verb might be an in-world action for other forms. Otherwise the meta flag is set in the Actions section.
Kerkerkruip adds a third layer on top - the “take no time” flag. This is so that looking/examining/etc don’t progress time. Could this have been accomplished without an extra layer? Possibly, I’m not sure of all the implications. If you were to try it again from scratch I’d try it without an extra variable and see if you can get by.