This may well be the intended behavior. In the mid-1970s, Gottlieb got more strict about turning off "when lit" inserts or bumper lights if the score motor was turning. Note the related anecdote at https://www.ipdb.org/machine.cgi?id=1089 about the score motor.
.................David Marston

Normal behavior for a Gottlieb, that's why it says "when lit".

Normal as dmarston and Garrett pointed out. You can watch this YouTube video to see for yourself what it should be doing.

Note: not all YouTube pinball videos are accurate but this channel is.

The “When Lit” indications on targets informs the player that the machine will not register a hit on a target when the motor is already turning and scoring a previous hit…. the targets’ lights should go out during this period.

As an example, if you hit a “50 Yards and 5000” top rollover, drop onto the pop bumper and get knocked through the “50 Yards and 5000” side rollover, the machine will start the motor in response to the first rollover and begin counting up your yards and points. During this process, additional scoring is disabled. The machine (likely) will not register the second or third score while still in the act of scoring the first.

For Gridiron specifically, while the motor is turning - pops, rollovers, 1 point targets, 100 point targets, the spinner and kicking rubber switches are ignored, or, more accurately, are ignored if your Motor 1C switches are adjusted correctly.

Gridiron is unique in that there is one exception to this rule - the outlane Touchdown. The touchdown will be queued and scored appropriately even if the motor was turning as the touchdown rollover was hit.

I remember that from when I had a Gridiron - *every* rollover lamp is always on except for motor runs, i.e. 'when lit'. Gridiron is a total point scoring game so doesn't have any logic involved with the rollovers, pretty unusual. Mine was in mint condition too, was made right in that era where solid state games had quickly taken over and a lot of the final bunch of EMs were retired very very early.

Not so much on EM Basketball titles but a really fun early solid state machine is Bally’s Harlem Globetrotters.

Lots of great billiards themed Gottlieb pins.

Sure Shot/ Bank Shot
Big Shot/ Hot Shot/ Pro Pool
Target Pool/ Mini Pool
Bank a Ball