I edited a mp3 file already on MC database and increased its length and copied the longer file on top of the older file and then reanalyzed. MC (30.0.73) reported the correct longer length (as do other players). MC and other players would properly play the longer song. However, when I played the same song using MC and a DLNA Zone (SONOS), the file cut off playing the end of the song by about the same length I had added at the beginning. Although I am sure what I am describing is a very unusual situation, it would be nice if an edited file made longer would play properly on DLNA. (When I looked at the file length through the SONOS app, it also reported the correct file length.) There is a workaround (below) which may give a hint as to the issue.
Workaround: The problem was "solved" by copying the file to a non MC imported folder, then deleting the original file from the folder where it was and clearing that file from the MC database (through the MC delete command - "remove from library and put in recycle" - and then cutting and pasting the the copied file from the non MC folder to the MC folder where the file used to be. Now that file plays properly to the end when using DLNA. (Deleting and restoring from the recycle bin did NOT solve the problem).
Edit: I tested the workaround on another lengthened file and deleting using MC by removing from datbased and sending to recycle and then restoring from recycle did fix the problem on the 2nd file I tried.