Switching lenders last minute, any legal cost risk?

Have a refinance (no equity take-out, just switching lenders at renewal) lined up with Lender A. They already charged an appraisal fee, which I understand is sunk if I don’t proceed, but would be refunded if I sign next week.

Now I’ve been offered a slightly better rate and incentives with Lender B.

If I don’t go in to sign with Lender A and switch instead, is there any exposure to solicitor/legal fees for work already started, or are those only incurred at closing? They were covering legal fees, which is why I’m unsure.

Current term expires April 19 and I’ve already rolled into an open just in case.

Trying to confirm if there are any costs beyond the appraisal if I don’t proceed.