docs: update known issues for fmp4 captions (#79)

README.md

@@ -66,6 +66,7 @@ Video.js Compatibility: 6.0
   - [Segment Metadata](#segment-metadata)
 - [Hosting Considerations](#hosting-considerations)
 - [Known Issues](#known-issues)
+  - [Fragmented MP4 Embedded Captions](#fragmented-mp4-embedded-captions)
   - [Fragmented MP4 Support](#fragmented-mp4-support)
 - [Testing](#testing)
 - [Debugging](#debugging)
@@ -660,9 +661,12 @@ and most CDNs should have no trouble turning CORS on for your account.
 
 
 ## Known Issues
-Issues that are currenty known with workarounds. If you want to
+Issues that are currenty known. If you want to
 help find a solution that would be appreciated!
 
+### Fragmented MP4 Embedded Captions
+Currently this project does not parse embedded captions from fragmented MP4 segments for HLS or DASH content.
+
 ### Fragmented MP4 Support
 Edge has native support for HLS but only in the MPEG2-TS container. If
 you attempt to play an HLS stream with fragmented MP4 segments, Edge