Last year, I applied for a research assistant position at a German university in the STEM field aimed at a PhD degree. I prepared all the documents required, including recommendation letters from professors in my current school. I also got an e-mail from the university confirming my application.
However, I was not informed about the status of my application for a long time (about two months), even close to the desired starting day for the PhD I had not heard back from them. I also checked my spam folder every day. So I sent an e-mail to the university to ask what was going on. They said that my application was rejected but it seems that somehow the result was not communicated, and they don't know why. I didn't understand the situation, but I could do nothing but accept the given result.
Soon after, I got an e-mail from the university informing me that they will open another hiring process soon. It says that they decided to hire a more convincing applicant at the time, but they hope that I consider applying once again. I never got this kind of e-mail before, so I'm now a bit confused.
Is it normal for German universities to announce new hiring to all previous applicants, or is this only for me? I might be overthinking too much, but I'm guessing they are just being nice. (Maybe as I was not informed of my previous application because of their mistake.) My supervisor said that it might be a positive sign, so he encouraged me to apply again. But I'm suspicious whether the university really wants me to re-apply. I was not even invited to the interview, and all I got was a short rejection mail. I won't apply again if the same result is repeated, as I don't want to waste my time. What should I do? Should I seriously consider applying again?