Using the latest release, selecting (highlighting) a single subtitle entry, then making changes under the Format tab seems to be working as intended.
Other non-selected entries are not affected if
is chosen prior to making changes.
Don't have Sriracha, so cannot test that here. Perhaps the font is incompatible with VP?? Tahoma works well.
File a bug report. https://tinyurl.com/ygvg54so Be specific about those marks. If possible, please Include a link to screen shots shared on MS OneDrive, Google Drive or the like.
You can revert to the earlier release; just install over the current version.
Depending upon your job, using text overlays in lieu of subtitles may be an alternative. Compose the text with your preferred editor, then COPY/PASTE the result into the VP text editor window.