I've heard before that R' Shlomo Eager speaks about (I believe in Yorah Deah Siman 28) a sofek if one is allowed to make a bracha on "achilas matzah" before the time of eating and be yotzee with that bracha later on. This is only something I once heard and it seems a bit unusual however the person saying it over was quite reliable. In any case it brought me to another interesting "sofek" ("doubt") May someone make the bracha "l'sheiv b'sukkah" in a part of the sukkah that is not kosher to sit in (for example under a "dofen akumah") then move into the actual part of the sukkah right after making the bracha? What about if someone is sitting in their house, may they make the bracha then walk into the sukkah? This would seem quite simple that it wouldn't work (or for sure lichatchila shouldn't be done) however I'm asking on the premise of sofek of R' Shlomo Eager.