When I unplug usb mouse and plug it back, I get

ButtonRelease event, serial 33, synthetic NO, window 0x4e00001,
    root 0x74, subw 0x0, time 26943984, (62,77), root:(1088,715),
    state 0x10, button 1, same_screen YES

ButtonRelease event, serial 33, synthetic NO, window 0x4e00001,
    root 0x74, subw 0x0, time 26943984, (62,77), root:(1088,715),
    state 0x10, button 2, same_screen YES

ButtonRelease event, serial 33, synthetic NO, window 0x4e00001,
    root 0x74, subw 0x0, time 26943984, (62,77), root:(1088,715),
    state 0x10, button 3, same_screen YES

ButtonRelease event, serial 33, synthetic NO, window 0x4e00001,
    root 0x74, subw 0x0, time 26943984, (62,77), root:(1088,715),
    state 0x10, button 4, same_screen YES

ButtonRelease event, serial 33, synthetic NO, window 0x4e00001,
    root 0x74, subw 0x0, time 26943984, (62,77), root:(1088,715),
    state 0x10, button 5, same_screen YES

ButtonRelease event, serial 33, synthetic NO, window 0x4e00001,
    root 0x74, subw 0x0, time 26943984, (62,77), root:(1088,715),
    state 0x10, button 8, same_screen YES

ButtonRelease event, serial 33, synthetic NO, window 0x4e00001,
    root 0x74, subw 0x0, time 26943984, (62,77), root:(1088,715),
    state 0x10, button 9, same_screen YES

events. This happens also on rmmod and insmod of usbhid.

It's evdev 1.1.5.

Kernel sends (EV_SYN, SYN_REPORT, 1) triple on disconnect and X
seems to treat it as button release or somewhat on reconnect. No other event is
sent. mouse driver seems to work fine.

See also suse bug 381543:
https://bugzilla.novell.com/show_bug.cgi?id=381543