Yes it does. Infact MCEBuddy now supports multiple subtitle tracks and extract/embeds them all even if you’re using a regular conversion mode (i.e. not the Rename only mode).
However if your case, your profile is invalid so MCEBuddy can’t proceed:
ERROR> 2019-08-23T20:07:09 MCEBuddy.Engine.ConversionJob → Unhanded error during conversion, conversion cancelled
System.Exception: Invalid profile, order is empty
at MCEBuddy.Transcode.Convert.GetConversionExtension(ConversionJobOptions conversionOptions)
at MCEBuddy.Engine.ConversionJob.GetDestinationFilename(ConversionJobOptions conversionOptions, VideoMetaData metaData, String originalFileName, Log jobLog)
at MCEBuddy.Engine.ConversionJob.Convert()
INFORMATION> 2019-08-23T20:07:09 MCEBuddy.Engine.ConversionJob →
I also noticed your profile is called *MKV Unprocessed*, no idea why there are *'s in the name or what the actual profile contains but it seems to be missing the order= directive.