I noticed a similar tweet yesterday, mentioning something about disruption till 1930. I can't remember the exact wording, but it was put out early evening. 

Forgetting the rights and wrongs of what has gone on in the depot and any shortage of drivers - surely whatever staff are left, are needing to be allocated across the day.
Theres some significant gaps in service to some destinations and those gaps could seriously inconvenience customers. 
Managing and allocating the resource effectively is something they need to be doing, whilst working to overcome whatever is going on internally within the depot. 

If the resource isnt managed or allocated effectively, then the longer term implications on customer perception and bums on seats could be catastrophic. 

Passengers need a reliable service to get them home after work to see their families, relieve kids from childcare or in some cases, get to work. These gaps in service aren't giving them that option.