Very odd glitch in one game, performance tanks when building more than a certain number of ships on the fleet build menu

Title. With a fleet selected and the build window open, the game's performance tanks incredibly hard the second you pass an arbitrary number of queued ships to build. I have tested this extensively and can find no rhyme or reason to what the cutoff point signifies. I can queue 7 Garda frigates without impact, the 8th one drops the FPS by 2/3. By the same token I can queue 24 or so scout corvettes before the performance hit, 8 gauss frigates, but only 4 or 5 colony ships. It doesn't seem to have to do with supply queued, cost queued, types of hulls queued... and when you press N to close the build window, the FPS jumps back up even with the units queued that cause the performance hit.

https://drive.google.com/file/d/1gF6UOy6mumxeYSUm6iucbexx1_MWjlUq/view?usp=sharing

That is the save game if the devs want to open it up and tinker with it. I tried switching to the test build on Steam, the issue persists.

What's interesting to me is that the performance gets worse and worse the higher the time dilation is dialed up. Which makes sense, the game is simulating far more stuff in a far smaller span of time, but what critical process goes over the "red line" when these ships are queued up like this? I am baffled and searching reddit, this forum, the Steam forums, etc has not produced anybody with the same issue.

I do think this has come up in other games but this is the first time I've really stopped and investigated it.