The game reports the flipper end-of-stroke switches as stuck closed, though they are visibly open.

Game reports flipper EOS switches stuck closed when they aren't: reseat the ribbons

Cause: A poor contact on a ribbon cable, likely between the CPU and the Fliptronic board.

Checks

• Remember Fliptronic EOS switches are normally open, unlike older games.
• Check the ribbon cables between the boards.

Fix

• Press down and reseat all the ribbon cables; replace any with worn connectors.

Systems

• WPC Fliptronics

Games

• Creature from the Black Lagoon

Related tips

• Creature from the Black Lagoon: "check switch F6 U.R. Flipper" error
• Upper left flipper button switch error on a two-flipper game: broken trace on opto board
• Reseat the ribbon cables before chasing odd behavior

Source: Pinball Repair help group!! (Facebook group)