I've noticed that when on wifi, I will not receive certain group texts. This seems to be number specific. The texts will usually come in either hours or days randomly while I'm not on wifi.
I've actually witnessed this several times on all of my past phones. My current phone is a first generation pixel. Turning off wifi usage is not a solution I want to use. I have downloaded other text messaging apps with the same results. It seems that a lot of other people are having the same issue on TMOBILE. I was wondering if anyone has figured out a work around?