Switch power cuts off when i insert or remove joycon in tablet

hi guys. i got this weird problem,
i play mario party. and 1-2 switch. they require the controllers be handheld while the tablet is on the dock.
when i insert or remove the joycon into the rail (Right side), the tablet power cuts off.
the tablet power is 90+% (docked) the joycon power is low to fully charged.
do i need to tighten some screws or something?
any controller sliding on or off does this.( irregardless of charge status on the joycon)
i play on handhelpd mode, no problems, unless i remove the joycon.
your advice is highly appreciated.
many thanks,