One of my guys wanted to torch a strip of modified to an existing modified to night seal our new TPO roof. I just about threw him off the roof.
One of my friends went to work for a new company and sent me a pic of their night seal, same thing, they friggin torched a strip of modified. I couldn't beleive it!
I'm not saying you should torch modified to TPO but it seems to be pretty common. If you check with the manufacturer of the product you are using they will be able to show you a detail drawing of how to to a night seal/temporary tie-in.
The information found in this post is not to be considered legal advice. The author of this post takes no responsibility for any losses that occur. Use at your own risk.