Some shadows become invisible after switching from "Distance Shadowmask" to "Shadowmask" on Mixed lighting mode?

I'm probably missing something in here but I can't see what.

I recently switched from "Realtime" to "Mixed" shadows on my main light source, and after I re-baked the lighting I realized that some shadows were either gone or became invisible.

Now, when I change the Shadowmask mode from "Shadowmask" to "Distance Shadowmask", the shadows become visible again just like how they used to.

Here is an example from my terrain, the tree shadows are not set to static because their leafs move, but terrain itself is static:

Shadowmask:

https://preview.redd.it/o3po618o3gsb1.png?width=1176&format=png&auto=webp&s=17c54a0f1ce2c28ccc2d098a75913844611f3499

Distance Shadowmask:

https://preview.redd.it/qqazrg8w3gsb1.png?width=1099&format=png&auto=webp&s=d03de5bbaf424c959dff33489a98a4ba17bf3c49

And here are my settings:

Lighting Settings

Main Light

The shadows also turn back when I set the "Lighting Mode" to "Baked Indirect" or "Subtractive", but somehow not "Shadowmask".

I'm against using Distance Shadowmask because it's more costly and I need to figure out why it works with Distance Shadowmask only, so I can use Shadowmask without such problems.

What am I missing?