As you get Gapless when you play local files (in the MC Library) from MC to the CXN using MC as the DLNA Server and JRemote DLNA Controller, then do you also get Gapless if you simply replace JRemote with mConnect?
If Gapless does work in that situation, but doesn't work when you try to play Tidal to the CXN, then mConnect is probably having the same issue as when people try to play Tidal via the WDM Driver and MC to a DLNA Renderer; streams of unknown length can't be played to a DLNA Renderer.
But it may not be that straight forward.
By the way, the DLNA Controller is involved in sending the SetNextAVTransportURI, which is what enables Gapless playback to a DLNA Renderer.
If you are using mConnect as a source of Tidal content, then is is really acting as a Streamer, and DLNA Controller for the CXN DLNA Renderer. That is quite a different thing. I assume that Tidal will play locally on the device when using mConnect.
Also, JRemote uses a mixture of JRiver MCWS and uPNP/DLNA. When playing to a DLNA Renderer, it must use the DLNA protocol. Basically, it uses MCWS and the JRiver Access Key method to connect to a MC Library Server, and DLNA for just about everything else, I think. I could be wrong.
PS: I've only ever checked out mConnect Lite on Android, so don't know its full capabilities.