Title is self-explanatory. Unfortunately I haven't got a recording of this happening, but I'll add it once it happens again. See
[media].
MC-146213
Loading bar on splash screen is able to extend beyond its black outline
Resolved
Fixed
7
(Unassigned)
Confirmed
UI
Minecraft 19w11b, Minecraft 19w12b, Minecraft 19w13b, Minecraft 19w14a, Minecraft 19w14b, ..., Minecraft 1.14.2 Pre-Release 2, Minecraft 1.14.2 Pre-Release 3, Minecraft 1.14.2, Minecraft 1.14.3 Pre-Release 2, 1.14.4
19w41a
Retrieved
I have this problem too in 1.14.4, it's perturbing, but it happens only once for me