2017 Lance 650 Factory Eternabond Roof Leak

If your out on the road I see no problem putting some putty on there temporarily. If your home and have time before winter, I would take off the EB tape that has gone puffy and replace as necessary. There was a thread about this very topic on LOA "Lance of America" sometime back. Forum members were indeed describing your very problem. I think, if I am remembering correctly the repairs in question removed all the EB and installed it in a more traditional manor. I am from Binghamton and it will start icing during the nights soon enough. I wouldn't wait as the freezing and thawing of the water will make the problem worse. Good luck.
Joe

https://www.rvwithtito.com/articles/how-to-remove-eternabond-tape/
https://www.mortonsonthemove.com/eternabond-tape/

I found many articles and none were negative. I thought they were interesting.

If it were me I would want to know why it is leaking so that I can repair it correctly. Fore example a few years back, I had a fantastic fan that was sealed by eternabond taped that was leaking. I removed the tape to find the plastic base on the fan had cracked.

I used a heat gun to heat up the tape which caused the glue to get soft and was able to peel the tape off.