Completely random leaks through solid geometry

[Freezebug]

I'm practicing stitching parts of maps together, which in practice isn't that hard. However, I've run into an interesting issue i've never experienced before.

Every time I compile the map, there's a different leak -- even if i haven't changed anything.
First compile run:

http://xayr.ga/share/2018-04/hammer_2018-04-29_18-19-482b5b39a1-ab78-47e0-8b82-96affe2c07bc.png

Second compile run: Same map, no changes, different leak location, leaking through completely solid geometry:

http://xayr.ga/share/2018-04/hammer_2018-04-29_18-24-4794026efc-9e1d-45ad-90f8-61b957b2692f.png

http://xayr.ga/share/2018-04/hammer_2018-04-29_18-23-1373e6ad0c-f1c1-4e08-b9e2-43e52b30696a.png

Third compile: Same map, no changes, differen--- yeah you get the point.

http://xayr.ga/share/2018-04/hammer_2018-04-29_18-27-56a531bf16-9519-45da-be8f-061e8fbd394c.png

http://xayr.ga/share/2018-04/hammer_2018-04-29_18-26-43e490e5b8-1ea5-4197-b32b-9c6113361a4e.png

I've been playing with source since 07 and have never run into anything quite as dumb as this. Any ideas?

[ficool2]

Disable radius culling, by clicking this circled R button. If that doesn't work, copy paste everything into a new VMF

http://tof.canardpc.com/view/2b442649-9c4b-4511-aa47-22279ffd840a.jpg

[Freezebug]

I've never had to do that before, but the latter option fixed it (Copying into a new VMF).
Thanks a bunch, this has been frustrating me for a couple hours now

[Instant Mix]

Occasionally hammer will shit itself and leave fucked brushes in your level. Check that there are no weird things occasionally by selecting "Check For Problems" in one of the toolbar menus. "Invalid geometry" is a fairly common one, if trying to find that brush leaves you nowhere, doing exactly as you did ( copying into a new VMF ) will solve it