@McLovin hi , first of all im new here and im not an expert also , since 6 months im testing wbs210 which is 1 of 3 APs i have in my network , i had the same problem , in the begining it starts with high ping times and if i leave Ap without restart etc for 2 days its crashing , i tried all possible firmwares for this Ap , changed antennas 5dbi tp link , (grey ones) 8dbi tp link (black ones with tp link logo markings) and finally found solution , Ap is incresing ping times only when antennas are in vertical position and after 1 2 days stops responding at all. My a is wbs210 V2 , the best position of antennas is to give them V shape or 90 degrees exactly 1 vertical and other horizontal , and since 20 days it works very good. 

@Senol , thank you for your interesting experience.

Is your workaround 'reproducible'? I mean, could you please restart the device, monitor it for a while and report here back?

Thanx

@McLovin  Sure i will report here in few hours , yesterday i tried firmware of cpe510 to upload it to my wbs210 and im surprised it works also well until now. But im not going to keep it there so will upload again the latest firmware and share results here ..

Thanks

@McLovin hi again , after testing my wbs210 for 6 months with diferent antennas and various tp link firmwares finally i found best settings for me . I am using my ap as wisp client. AP is unstable when both antennasare in vertical position , tested it several times and each time dhcp clients loosing ther ip's. There is 1 computer 1 mobile phone and 1 iptv box conneted to this ap and all this devices loosing ip after 4 5 hours . Ater resetting wbs210  it was working good again for another few hours. In wireles settings page ii disabled Short GI and QoS . With QoS and Short GI disabled iptv box works without any problem , when they are enabled and i receive some whatsapp call i thng ap is giving priority to the phone and momentarily i see iptv buffering and stops video for 1 2 seconds and starts again and so on. Normally it should be opposite if im not wrong.Here are some screenshots from my setting. If you want me to test something else just let me know i will try to do my best. 

Thanks.