High latency wireless inter vlan traffic

[it_ejvnior]

Hi.

I'm here to post a strange behaviour over the inter vlan routing.
The core switch is a HP5500HI and I have 5 access switches below the core switch (HP 1910).
All the trunk links are 2 Gb using LACP protocol to make an etherchannel.
In one of the access switch I have two access points using a different vlan than the native and three wi-fi networks, each one in a different vlan too.

When I'm using the corporate wifi network and start a ping -t destined to the access point that I'm connected, everything goes fine and suddenly the latency increases and keeps raising until 3000ms or more and I got no response.

All the access point configs are the same because of the user number using wireless.
RTS:400
Frag Threshold: 1514
Beacon: 100
DTIM: 1
My laptop uses 2.4Ghz frequency, but the AP is dual band.

What I did today? I unbundled the etherchannel maitining one port as a trunk port and the STP disable the other port. The latency is better now but sometimes raising a bit but I don't lose packets and the recover from 2000ms to 2ms is faster than before.

Checking the port statistics and no CRC errors, input, output, runts...

What could be this behaviour? Or is it "normal"? I don't believe  in the second choice.

Thanks in advance.