Say Gapejaw Bog stadium and Ting-Lu ex with "Cursed Land" Ability are both in play. If I put Lumineon V onto the Bench, can I use its "Luminous Sign" Ability or will it be blocked because it has damage counters on it?
Since Luminous Sign and Gapejaw Bog are simultaneous effects, it is up to the player to choose the order in which they will be applied.
Source: TPCi Rules Team (2023-07-13)

Relevant cards

Note: All applicable cards may not be listed below.
SV2_127
SV2_127
SWSH9_40
SWSH9_40
SWSH10_142
SWSH10_142