When starting a new game in survival mode (have not tested other game mode) the stats that you roll for when creating your initial dupes, will sometimes not correctly load and apply when the game starts.
For example. If I elect to start with a digger with +7 excavation and a +3 excavation bonus, when the world finally loads and I check the "Skills" page to verify the dupe's stats, it might show +7 construction and +3 excavation, or any other variation of stats, but not the +10 excavation that it should show.
The occurrence of this bug appears to be random, and does not always happen, however, it happens enough that it warrants checking the dupes stats at the beginning of every play through. When play is continued and the dupes are ordered to start digging, based on the delayed dig speed of the dupe that's supposed to have +10 excavation, I would say that it's' not just a graphical error on the skills page, but that the wrong stats are actually the stats being applied.
Create a new playthrough on survival mode. Elect your starting dupes to have a specific set of skills and bonuses. Check the skills page upon entering the world, and see if the skills listed match what you had rolled for on the creation page. The frequency on my end appears to happen at least 1 in 10 starts.