do coins break alot, after mining some coins I have found some algos and wallets seem stable, where as some coins they release wallet after wallet to fix issues.
are some algos less prone to bugs then others?
It's not the algorithm but the code it's running on. Assuming the code is nice and tidy you should have no problems, however, there are other variables that cannot be accounted for.
When Ember was all the rage people were staking that coin like crazy. Then one day it was discovered that if there were more than a certain number of coins in a single input then that input would stake at a greatly reduced reward or even zero reward. This was a result of the interest rate being jacked up so high. The original developer never tested it and when the new team took over they never thought to test with inputs that high because they thought it would be okay.
This staking bug played a huge part in killing Ember.