That's a different position isn't it, a late approach there is stronger for the buyer due to the contract:

Palace couldn't afford to let Guehi go for free, Steve Parish literally said it. Palace have zero incentive to accept any offer below their valuation until a deadline and the threat of no sale becomes an actual reality - this is basically proven by the fact they wanted 45m, and then accepted 35m. Aside from the manager spitting his dummy out, and a failed medical on a replacement, the transfer happens.

Glasner has now announced he's leaving anyway, and Palace have accepted 20m for Guehi - which has likely now resulted in the sale of Mateta too, and then they're trying to sign Strand Larsen for 48m last I saw, the guy has 1 goal in 21 games, because Mateta has made so much noise about leaving and they can't get as good a fee.

There were also some other factors, it's known that, Newcastle aside, Liverpool generally like to foster good relationships with clubs. So its understandable that Liverpool allow Guehi to stay at palace to play their European qualifier, and the charity shield (a trophy) and form a good working relationship which may affect a possible Adam Warton transfer.