Based on the stacktrace, the error seems to be coming from a corrupted info.json file in the sync folder.
For reference, I'm including full error (with stack trace) below:
SyntaxError: Unterminated string in JSON at position 2048
at JSON.parse (<anonymous>)
at /tmp/.mount_JoplinG1asF7/resources/app.asar/node_modules/@joplin/lib/services/synchronizer/syncInfoUtils.js:61:27
at Generator.next (<anonymous>)
at fulfilled (/tmp/.mount_JoplinG1asF7/resources/app.asar/node_modules/@joplin/lib/services/synchronizer/syncInfoUtils.js:5:58)"
For others and probably myself in future, the debug log does not show the problem file together with every occurrence of the "Unterminated string in JSON at position x" error.
Keep searching the file until you get the problem filename.