Actually, this is functioning as intended, though I definitely need to change it.
Before I added features like entity filters to the mod, boilers would eat up so much fuel compared to everything else that other entities ended up being starved occasionally. You were forced to use Loader Chests for boilers even if you'd rather use a belt, because I hadn't yet found a way to limit their fuel type or let users filter them out.
So, I eventually hardcoded boilers as the only entity type that the mod completely ignores, and a few users said they liked the idea a from a balance perspective, so I never changed it. Now, with entity filters, there are much better ways this can be handled by the user, so I'll turn it off in the next update.
Thanks for using the mod, and thanks for your feedback!