The title says it all.
Recently I've started using Smooth Boot Forge in all my modpacks, as it is an awesome mod, but in some recent testing I've encountered an issue with all the posible downloads of Optifine 1.16.5 (G6, G7 and G8).

The main problem is on the chunk loading:
-Once a world is created, the first thing I noticed was chunks not loading absolutely. I could move and mine but the chunks where not there. At around 10sec after, they start appearing in random locations and in order to make the other random chunks not showing 'show', I had to interact with the blocks on them chunks.

I removed absolutely all the mods and started activating them one by one, until I got this result.

-Steps to reproduce:

1. Install Optifine_1.16.5_HD_U_G6/7/8
2. Install smoothboot-forge-1.16.4-1.2.2
3. Create world and there it is

Most probably it has something to do with smoothboot-forge being for 1.16.4, but as an excuse, many other mods are from lower versions and still work.