Huge decrease in fps when looking at a mangrove swamp

steps to reproduce:

1. make a new world in 25w31a
2. look at your fps when you spawned in and remember that number (if you spawned in near a mangrove swamp, make a different world till you spawn somewhere else)
3. if you didn’t spawn in or near a mangrove swamp, then do /locate biome minecraft:mangrove_swamp
4. teleport to the mangrove swamp
5. look at the fps counter

expected result: (what is supposed happen)
fps counter before looking at the mangrove swamp: the normal amount that you set in your settings (for my case 60)
fps counter when looking at mangrove swamp (about the same amount as in your settings (for my case it should have been 60)

actual result: (what did happen)
so I followed the steps provided;
1. made a new world in 25w31a (and I did /seed when I spawned in that world→ this is the world seed that I got: -1105659044264618450 just in case if you want to check with other fps and video settings)
2. fps counter before looking at the mangrove swamp: the normal amount that you set in your settings (for my case 60)

3 didn’t spawn near a mangrove swamp so I did /locate biome minecraft:mangrove_swamp (when I clicked the chat message that showed up): it gave the following command: /tp @s 839 155 -2213
4. I teleported to those coordinates
5. I just turned around and just looked at the mangrove swamp and then at my fps counter and it said 26 and about 2 seconds later it stabilized to around 30 to 40 fps which is still not near the expected 60 fps


I don’t know why this happens, but this is a huge fps drop and the thing is, if I look away from the mangrove swamp my fps counter instantly goes back up to 60