As I mentioned above, Bitcoin Core nodes will request and store blocks in competing chaintips with the same PoW as their best chaintip, but they will not announce those blocks to their own peers. Even if Foundry had announced it after having found it, the block could have not made it beyond the Foundry nodes’ peers if they all had seen the competing block before it, or it would have possible made it another hope from a few peers before getting blackholed.