The labels for Skill modifiers disappear after editing any information on the statblock, e.g. HP.
The labels stay missing after closing and reopening the statblock.
Opening the "Sheet" selection window and re-selecting Monster Blocks and therefore reloading the statblock will bring them back. However, they will disappear again on the next edit.
On load:

The issue, shown after editing HP:

I am using Foundry 10 (Build 291), the latest dnd5e Game System, and the current Monster Blocks module (3.3.5)
The labels for Skill modifiers disappear after editing any information on the statblock, e.g. HP.
The labels stay missing after closing and reopening the statblock.
Opening the "Sheet" selection window and re-selecting Monster Blocks and therefore reloading the statblock will bring them back. However, they will disappear again on the next edit.
On load:

The issue, shown after editing HP:

I am using Foundry 10 (Build 291), the latest dnd5e Game System, and the current Monster Blocks module (3.3.5)