I did some more troubleshooting and not only discovered a bit more details on the problem, but a really odd workaround.
From what I can tell, it seems to be an issue with the UI refreshing itself. This may explain why this started occurring since Patch 1, since that was the patch where the UI performance was overhauled.
I tested this thoroughly by entering turn-based mode and standing next to a candle. If the candle started dim, but then became lit, Cloak of Shadows would still be bright as if I could cast it, but hovering over it would *show the red text saying that I need to be obscured in order to use it*. I would enter the targeting phase of the ability, but ultimately wouldn't be able to use it since I was not obscured. It's odd I could even enter this phase, but it ultimately works the way it is supposed to.
IF, however, the candle was lit at the start of the turn, then was dimmed by the player, Cloak of Shadows would be grayed out and the game blocks you from using it DESPITE the fact that the same red text was NOT present and your character is in fact obscured.
This bug works EXACTLY the same with Hide, both the Action and Bonus Action. If a character starts their turn threatened, they cannot use Hide even after leaving the Threaten radius *unless they are attacked on the way out*. While this sounds like it is working as intended, it isn't. If you are using Darkness or have the Mobility Feat, both of which allow you to walk away from melee range without getting hit with an Opportunity attack, then you cannot use Hide.
Based on this finding, it appears the issue solely stems from the UI simply not catching up with conditions or not refreshing properly. This is showcased by the issue with Hide where you have to get damaged by an Opportunity Attack because your UI because briefly unavailable while the attack is happening. Getting attacked or performing any other action seems to refresh the UI. As such, if I melee attack a target then walk away (with the mobility feat) then the UI thinks I'm still next to the target because that's where I was at the beginning of the attack. Conversely, if I use a ranged attack, then ENTER Melee range afterward, Sneak will be lit up as if I can use it because I was outside of Threaten range when the UI refreshed.
After messing around with this, I found the weirdest work around: locking/unlocking the hotbar. I'm not joking.
I noticed that if I ever found myself at a time where I *should* be able to use an ability like Cloak of Shadows or Shadowstep, but it is dimmed as if I can't use it, simply locking or unlocking the hotbar immediately forces the Hotbar to refresh, causing the abilities to me useable again.