It's common for the HR manager who originally signed your reference letter to have left the company by the time you actually submit your Express Entry or provincial application. Group members advised not to overthink this in your Letter of Explanation.
What group members advised:- Don't proactively mention in your Letter of Explanation that the signing manager has left. There's no requirement to flag this, and doing so can raise unnecessary questions.
- Keep a full, consistent set of supporting documents — payslips, bank statements, offer letter, contract, increment letter, ID card, and leaving certificate — so the reference letter is corroborated even if the signer can't be reached again.
- Be aware that IRCC or the province may attempt to verify your experience by contacting the person who signed the letter. If that person is unreachable (no access to their old email, company under new management), this is a known risk worth being aware of, though it doesn't mean your application will fail — it means your other supporting documents carry more weight.
The main risk flagged in the thread: if verification calls happen and the original signer can't be reached, having strong secondary proof becomes essential.