Help: Drop shadow is creating a strange outline in one text

[aridavid5]

A bit of background. I have 2 text layers that are a duplicate of one another. However, drop shadow is acting weird on one of them. I even duplicated the one working again to replace the other, and I got the same error.

In the top screenshot you can see how I expect it to work (how it always had before), and in the bottom one you can see that it is creating a weird black outline.

Drop shadow error https://imgur.com/a/0ojm7Fb

EDIT: After changing the precision, to interger instead of floating point, I stopped getting the error. Now I'm even more confused.

[tmanni]

These weird black pixels are out of gamut pixels (pixels with negative values).
Use the Color Picker and observe the values in the info window.
In the case of Drop shadow, it happens when the opacity value is higher than 1.0.
You can get rid of them by using Colors > RGB Clip...

Out of gamut pixels only exists for floating point precision image, where pixels can take any value.
In integer precision, pixel values are automatically clip to a positive range, e.g. [0, 255] in 8bits.