Due to difficulties obtaining a reference letter from one of my past employers (company now closed), can I change the working experience information in my PR application? Do they cross reference the information given in the express entry profile to what you submit after the ITA?
As long your CRS is above, after removing that work experience from work history, what was required for that round of invitations, you are fine. If your CRS falls below the minimum, decline the ITA and re-enter the pool.
Note: If you choose to remove the work experience from work history section and continue with the application, make sure you still add that work experience in the personal history section, so, that there are no gaps in your 10 year history. Proof for stuff mentioned in your personal history are not required. You need to account for all past 10 years in your application.