the Linux kernel has been FOSS since day one; however, all Pentium IIs and AMDs at the time suffered from the F00F bug, and that one had been around for at least 5 years at the time it was was patched. That was both a software and design flaw in the CPU's architecture as well as the kernel.
Same goes for the Spectre and Meltdown bugs, which affected every CPU except ARM. Intel's code for it was FOSS, and numerous developers, including Linus Torvalds himself stated it to be complete garbage and implemented a better solution.
To answer your question of why this is coming up now, this all stems from everyone taking more forensic looks at code due to the LastPass breach. Everyone is on edge, so everyone is getting a deeper look into their implementations.
BL.
So when you say "a bug was found" you mean that someone found a work around to breach or do you mean people actually wrote the code, saw the code, knew about it all along and just ignored it?
Can we assume closed source software is at a worse situation since not as many people read it and review it? For example , can we assume something like Dashlane is filled with security holes except that no one can detect them as easily since its closed source?
also, if I increase the hashes iteration in the settings, are we on the safe side now? and why doesn't Bitwarden just auto do this for all users?