I found another example of italics in a SRT subtitle where the rendering cuts off the last letter in the line.
Just copy & paste this in a file with the extension .srt, and use it with any video file (I used a 1080p file which is upscaled to a 4K resolution):
1
00:00:01,981 --> 00:00:24,858
<i>being the one to close off</i>
<i>her own escape route.</i>
The subtitle font settings are:
Font = Trebuchet MS
Font style = Bold
Size = 12
Script = Western
Maximum subtitle resolution = Unlimited
It looks like in the attached screenshot, with the final "f" of the first line being cut off.