Failure to meet work standards isn't disqualifying but changes to time and location like that aren't written up as failure to meet standards, they're written up as job abandonment, which itself is considered a type of voluntary resignation and is therefore disqualifying. The law differentiates between showing up but being bad at the job and not showing up at all, and constructive dismissal laws exist to prevent employers from manufacturing job abandonment in order to disqualify an employee.

One thing I learned in researching this is that constructive dismissal only applies where the employee has resigned rather than being terminated. It's not a non-voluntary resignation, it's a voluntary resignation that is coerced and is therefore an exception to the unemployment laws that would normally disqualify you for resigning voluntarily.