I have been playing from my phone during the day mostly, and I've had only a little lag/502 errors. Minimal for the number of pages I am opening/loading. (Continuously buying drinks at Remy's) There is a chance, that the problem is a local issue. I think this because I don't play on my phone much, like at all. Only started b/c I'm working during this anniversary celebration, and didn't want to miss out. Just a suggestion, and it may or may not work, and you may have already tried it, but try clearing your cache, history, and cookies "for all time." Completely clear your browsing history, close out the browser, and reopen.
Please remember, this is just a suggestion, and again, it may or may not work, but it has significantly reduced the number of errors and lag I have gotten in the past, and since I only started playing on my phone all the cookies there are current. Sometimes errors are due to corrupted/old cookies in the browser.