If anything, making it open will help you fix bugs. (fwiw, I’m building an open source saas myself, see profile, so my opinion is clearly biased.)

What I’d reconsider instead is the free forever. If you’re already open sourcing, users can already run it “free” (i.e. at their own expenses). I personally wouldn’t make a free saas, unless 1) it’s b2c and 2) you have very strong reasons to.