Equipped Elemental charges with Protective light, Elemental ordnance, Seeking wells and bountiful wells. Throw a Void vortex grenade, pick up wells and it does proc charged with light. https://m.youtube.com/watch?v=T5-ZrJc69gM. Edit: So, after further testing, it appears this is a bug with having the stag exotic equipped. If you have the Stag plus any mod that charges you with light, while having protective light equipped, it does not work.
I'm having the same issue as OP. I'm not running Stag though and I've swapped around armor to confirm the armor doesn't appear to be the issue for me.
When picking up a well with Elemental Charge mod equipped, *and* Bountiful Wells, I do not get charged with light whether picking up one or both wells that are generated though my ability cooldowns do decrease normally.
When I unequip Bountiful Wells, while keeping Elemental Charge equipped, then I can get charged with light when picking up the one well that dropped. I've swapped around armor and equipped the mods to different pieces or armor but the same result occurs - unable to get charged with light when equipping both Bountiful Wells and Elemental Charge.
Note - Also unable to get "Argent Ordenance" mod nor "Explosive Light" weapon perk to activate when having both Bountiful Wells and Elemental Charge equipped. I've confirmed these mod/perk do activate with Elemental Charge as long as I do not have Bountiful Wells equipped.