Usually when idle for a few seconds sometimes when in active use Log entries: May 15 22:08:27 lex kernel: umip_printk: 7 callbacks suppressed May 15 22:22:43 lex kernel: PM: suspend entry (deep)
There's not enough information here for me to assign this bug. Please seek support in Gentoo support channels, and feel free to reopen if you can provide more information.