Couple of questions about troubleshooting a problem/RMA

Hey ladies and gents, I have a strange issue with my N5. I am losing data connection despite having a 4-bar LTE signal. Most of the time, I will catch it at work while streaming music from Spotify/Pandora. Once in awhile i'd catch it while browsing Facebook as well. It will show a 4-bar LTE connection, but the apps will report "no data connection available." I've tried surfing Chrome when this problem arises and it says "You are Offline." I found a temporary fix - turning Airplane mode on/off or restarting the phone.

Has anyone ever heard of this, and does anyone have any suggestions. I was running SlimKat before, but now i'm on stock 4.4.4 with ElementalX kernel, with the issue crossing multiple ROMs/wipes.

I also just got off of chat with Google support. The lady is emailing me some troubleshooting steps, and wants me to contact T-Mobile as well. If the problem is still there, she wants me to RMA. What are the steps needed in order to do so. Some quick searches brought up factory images but I haven't found anything recent, and want to make sure I have all my bases covered.

Thanks guys!

Sorry for the late reply, been pretty busy the last couple of days. Glad to hear that Google doesn't care about the unlocked bootloader! I'll probably just return completely to stock and return it like that IF I have to.

However, I think I may have fixed the problem. I altered my APN settings and changed IPv6 to IPv4 and it seems to have fixed my problem, at least for now (the problem is random so i'll have to use it for awhile to make sure it really is fixed). Anyone else ever heard of this problem, or this fix, especially on T-Mobile?