When pillagers can't enter village during a raid, it causes various issues.

I have an underground base, below a mountain, with a trading hall which seems to count as a village. There is no access from the surface except through a single door. The areas where the pillagers spawn are at least 36 blocks above where the trading hall is, sometimes as much as 90 blocks above if they spawn at the top of the mountain. 

Issue #1:

In order to fight the raid, I have to leave the base and the raid bar disappears. If I finish the last wave while the raid bar is gone, I don't get the hero of the village. I've only been able to circumvent this by having a second player stay in the base with the raid bar on their screen - then if I finish all the waves I get the hero of the village effect.

Issue #2:

If I kill a captain ( with the banner ) I get a new bad-omen effect since I'm outside of the village. I have to go back into the village to initiate the next wave, at which point the bad-omen effect goes away. I'm not sure if it adds additional waves or not, but the real issue is on the final wave. If I get the bad omen effect while completing the last wave, as soon as I re-enter my base, an entirely new raid starts - creating an endless cycle. I've found that if I re-enter the base to clear the bad-omen effect prior to finishing the final wave - it's okay as long as the last pillager to kill is not a captain.

Issue #3:

I got the bright idea to create 3x3 tunnels which would route the pillagers to a door which entered the trading hall directly. I figured this could solve the issue where my raid bar would disappear if I routed the pillagers to me. I created entry points around the mountain where I was observing pillagers spawning. Despite the route to the village being right in their face, they insist on trying to walk into the side of the mountain and won't path-find through the tunnels I created.