Laars Boiler and Error 10

We have a Laars tankless boiler and it always smells like gas (propane) outside our house. It's not the slight smell you may experience at the start of a cycle. It smells!

It smells enough to have various technicians come look at it, but no one could figure it out. We finally switched propane companies and they concluded the smell was coming from the tank. I believe that was partially true and it's been replaced.

But, the smell continues and can even be noticeable around the front of the house (the exhaust is on the side) up to 30 feet away. That said, we have Error 10 messages that have occurred only a couple of times, but have begun to occur with far more frequency. Only in recent days, has it happened all the time - a hard lockout where the boiler has to be reset.

So, I'm guessing that the gas we've been smelling all this time is from the lockouts - that the boiler is spewing non combusted gas because it tries to fire 8 times before the lockout. This would be why unusual levels of gas odor are noted outside the house.

So, is my theory correct, that we've been smelling gas all this time because of a failed combustion process and the gas gets pushed out multiple times during the process?

And, if this is true, do we run a major risk running the heat pump that is very close by (before this issue is remedied)? This is important given the heatwave that has descended upon us here in NY. This boiler has been so frustrating that, even after just five years of ownership. I'm ready to have it replaced (I'm getting an estimate tomorrow). But, in the meantime, is there a major risk having a heat pump in the close vicinity to the vent pipes of a boiler failing by way of Error Code 10?

Thank you!

Brian