routing – Why redistributed routes do not overwrite the original ones?

I am looking a bit into mutual redistribution and I am trying to find out how a router decides which routes to redistribute and why.
R1 –ospf– R2 –rip– R3
Imagine the above scenario, in which R2 is learning about a number of remote networks from both R1 and R3.
If on R2 I redistribute RIP routes into OSPF, RIP redistributed routes will appear as type 5 in R2’s LSDB and it will advertise them towards R1. But since OSPF has lower AD than RIP, what stops R2 from simply overwriting RIP routes that it originally learnt from R3, with the same routes it has in the LSDB due to redistribution?
I’ve searched through a lot of documents and there are some rules redistribution follows, but I couldn’t find an answer to this one.