/Remake is not working consistently

In my most recent match, there was an ally who was disconnected from the start of the game until 19 minutes in. Told my team to try and survive until 3 minutes for /remake and we did (first death was at ~3:40). However, we were not prompted for a /remake and when I tried to manually put it in, the game stated that "a player must be disconnected for a /remake to occur". The ally had never purchased items and was spawned from the start of the game directly in the center of the fountain (an indicator that it was a disconnection rather than the player just not being there).

P.S. This is not meant to shame the ally in any form, it was stated that the issue for why she was disconnected was from computer issues, so don't blame her or anything, this is an issue with Riot's system not working properly.