This document will address the issue of the Enable Media Replace plugin not working as expected.
When using the media replace capabilities in the Media Library (provided by the Enable Media Replace plugin), the user must choose between two media replacement types. The first option - to just replace the file - works just fine. This means that you can replace the contents of the file (example: update an image to a different image), but the file name will remain the same.
The second option, to 'replace the file, use the new file name, and update all links' to this file does not work as expected. Specifically, the option to update all links and use the new file name does not work in Text Blocks. Please note that there are instances and page elements where this function will work (example: images in featured content blocks will get updated). The primary place this won't work is Text Blocks but other page elements may also be affected.
Unfortunately, there isn't a good workaround for this. If you must update the file name as well as the contents of the file, it is recommended that you manually update the links to this file in the Text Blocks. You could also just choose to use the first replacement type and just update the file but not the file name.