The secret door in broken helm hollow is surrounded by a blue magical aura that makes the same noise, as (I THINK) a lightning spell. It's really odd cause I can't find any quest reason it would have this aura or the sound effect and I don't use magic with my current character except in enchanting so it definitely wasn't like a lightning wall or anything, and the only enemy that ever inhabits the cave are 4 levelled bandits. (This time it was a Khajiit Bandit thug, a bandit marauder a bandit highwayman and a bandit chief) none of whom were spell casters. It hasn't impacted my game any, I can still open and close the door and I did the quest relating to it aswell as an "ancient power" quest for Feran Sadri, (that's when I discovered the glow) Just found it interesting and thought I would share it with you guys as I can think of NO plausible explanation for this lol.

Sometimes when I cast a spell and quickly change the spell mid-cast the sound and glow stay in the area I cast them until the area respawns. This may have happened somehow in your game. Have you tried leaving and waiting for the area to respawn? If memory serves the area should respawn in 30 in-game days. Other than that, no idea.

Well the sound is gone but the glow's still there lol. Thanks for the response. It doesn't bother me or anything, I just figured I should share it cause I found it interesting, that and I thought maybe I'd come across an unjournaled quest or something like that lol.

Enemies casting spells will do it too.
I've seen way too many a secret door or vampire coffin glowing in the aftermath of a battle where someone used magic.

Thanks it must have been some spellcaster at some point or another then haha.

Never seen that before lol. Then again I just got attacked in the rift by three "bounty hunters" at once none of whom even had a bounty letter lol