After Greencard

I been reading alot here, first, I really would like to thank everyone commenting here, It is really very helpful.
I have a question regarding Travel, has anyone traveled outside of the USCIS before filing the I-751, I traveled back home alone due to covid in the family, and there was a lockdown etc. so i took longer than expected, and i missed my flight. I came on February instead of December ( so time spent outside of the US was around 2 month). When i tried to use the machines in the airport, there was a mismatch between nationality in my passport and GC, because i was born in a country but hold the citizenship of another country and GC shows place of birth not nationality. so i went to the officer and they took me to a room, they stamped my passport with ARC, which i don't know what it stands for. and that interview took longer than our AOS interview. the officer really asked me about every possible thing, things they didn't ask about in the AOS interview. he even asked me to show him my instagram account.
I have no idea what were the reasons for this, i didn't even ask. and as now i am reading here and preparing my ROC, I am scared and concerned. My spouse is telling me that all is gonna be alright, i am just being stressed out of nothing, but while reading some of the experiences here, i m getting more nervous. Anyone with similar experience ??
Thanks