1. Are these APs on the same switch? or in same VLAN? This is just to check if what is the status of DHCP. As the issue you described, can be due to device not releasing the previous IP and upon reconnecting, it get the new IP and starts working.
KB: yes, it is the same router, switch and VLAN. imaging there are three ports, (1) to Huawei FAT AP, (2) port to my PC, (3) port to Ubiquit AP.
When my phone connected to (1)(sometime back) however there is no connection, i did check the console and is connected and fine, but flat throughput. i dint notice the IP change either. for (2) (3) is working fine.
2. What is the distance between these 2 APs? If they are close, please manually change the channels for these so there is no co-channel interference.
KB: the distance between two AP is around 10 meters apart (both same SSID). both AP reside in a different room, i dint set the channel however when i close to one AP with 3 bar, another AP is 2 or 1 bar only.
i can turn off one AP for testing purposes if you want.