Closed caption will not export

I have a 10 min video that I has added closed caption to. I have exported the video with an .srt sidecar file. However, when I play back the video with the cc there is one segment of dialogue that does not appear as closed caption. It's as if that portion of video did not have a cc typed out in the original cc timeline. I have tried to re-export a couple times and even deleted the said clip, saved the project, then retyped the cc for that portion of dialogue and export once again. Only to have the same result. No cc for just that one spot of video. Any suggestions for fixes. Film is entered in many festivals and I need to fix this for a proper and accurate playback for submission considerations.