Unregistered subtitles are moxibustion

What is your operating system?
Windows 10

What is your Shotcut version (see Help > About Shotcut)?

Can you repeat the problem? If so, what are the steps?
While editing, I noticed a problem with a subtitle bar that I didn’t register for for 1 frame. This is the first time I have experienced this problem after updating to the latest version, and sometimes the subtitles for that 1 frame appear or not. It’s hard for me to know the exact conditions of the error. I tried to print the video, and when I saw the result, I checked that the subtitle bar was output in 1 frame and entered the video. Sometimes it disappears if you leave the shotcut as it is, but I checked that the subtitle bar is created again. I checked the subtitle bar I registered just in case, but the subtitle bar did not exist in that location, and the subtitle bar appeared and disappeared even though I had never made any modifications. Again, it’s hard for me to figure out the conditions of the occurrence.

You did not provide steps. So, we developers do not know how to identify the bug to fix it. A bug in your project is not a bug in the software. You need to recreate the problem in a new project, write the steps as you do it, and paste the steps here.

Maybe you made a mistake. You need to look in Filters (whatever that is in Korean). You might have a text filter added but trimmed down to one frame. Also, it is possible you have a text clip that is only 1 frame long, but too difficult to see at the current timeline zoom level. You need to zoom into the timeline further to look for it. If you still did not find it you can upload the project file here, and maybe someone can find the problem.