Every year in january we process a big task with our system. While the performance during the task was above average the maintaince follow up is currently having a lot of trouble with jobs running too long and out of their respective time schedule. Therefore I am tasked with the optimization of those maintaince jobs and I am doing thusly the most thorough code review the system has ever seen. As I am good with analysing code I am also doing a lot of bug fixes.
This means I see lots and lots of bad or completely wrong code and implementations. My question is: How can I deal with that in front of my coworkers?
I hate it if I cause a bug (which I guess happens to everyone sometimes) and someone else fixes it without telling me about it. Because then I cannot learn from my mistake. On the other hand I do not want to be the guy on the team who is constantly nagging about how everyone else has to do his or her work. Also I am a bit wary of my own hubris. I do not want to find myself in the position that I start looking down on coworkers just because my biased mind thinks my code is superior. Currently I am not checking who has caused a bug I just fix it. I am not sure whether this is the best way to go.
I am a Junior level developer and English is not my mother tongue. Any advice (and grammar edits) are highly appreciated. The team follows the Rational Unified Process framework.