The bug
You cannot interact with light blocks if it the light block item is in your offhand. This is inconsistent with barrier blocks and structure voids.
Linked issues
is duplicated by 1
relates to 1
Attachments
Comments 12
Yes, and that bug was fixed. So this one should be.
Video attached.
Can confirm in 21w14a.
Can confirm in 21w15a.
Can confirm in 1.17.

Can confirm in 1.17.1.
Can confirm in 1.18.1.
Can confirm in 1.19.
Can confirm in 1.19.2.
Relates to MC-83003