all members randomly getting reset to default skin
 

my site is having a problem similar to this.

www.yugiohforums.com

vB 3.8.3
default skin = light default

system is set to allow members to choose their skin

pick any skin other then default.
go into one of the forums example
click on a thread, then click back to forum, then click on a different thread...
eventually (usually only take 3 or 4 threads) you will see that it jumps you back to default skin when you leave the thread and go back to the forum.
at this point the issue becomes 100% reproducible for that skin. set it back to the non default skin you were using, click on that thread you were looking at, then when you click out of the forum you will be set back to default skins.

i have gotten this to happen when clicking from forum to thread back to forum over and over. i also got this to happen by clicking from "new post" to thread back to "new post" over and over again.

i have reproduced this with each of my non-default skins.



i appreciate and information or insight.
thanks