Musescore 3.5 opens duplicate copies of the score being opened. How to prevent this? Pic attached. Also Musescore 3.5 cannot open MSCZ files saved from 2.x.

I have attached an example of a MSCZ file created in Musescore 2.x opened in 3.x.
By the way, I have been using computers since 1980 starting wing an Atari 8 bit plugged into a black and white monitor. I them moved to an Amiga and then to a PC. I have been building my own PCs since the early 90s. I have extensively used music, graphics, and 3D software every since. I learned 3D from Tom Hudson who wrote Cyber Space for the Atari. He taught me to program in Forth for the Z axis. When Atari went out of business he started 3D max. I have used 3D graphisc for video programs and so on. I later used these program to explain the cause of language disabilities which include reading disabilities. I have a reading disability myself and obtained 3 master's degrees and the last in Education and Counceling Psychology which enabled me to get a license. I concentrated on adults and young adults with these disaqbilities and ADHD in an effort to understand the actual cause. I did and for over 30 years with 80% to 90% of clients having these disabilities I have never found an exception to my undrestanding of these disabilities.
If one has a reading disability is is pervasive to all and any language including music. I have played the piano all my life but never had a teacher thgat understood a reading disability or accepted that I could not learn to read music. A reading disability has nothing to do with learning anything. It is and inability to create an acurate internal image of the external image of a word or note on a page.
Several years ago I asked if anyone could write a plugin that would put the names of the notes in the noteheads.
I was absolutely shocked that the next day I received resopnse stating that none of the programmers knew anyone with a reading disability who played a musical instrument and that this should be part of the core program. The reason is that music teachers do not understand the true nature of a reading disability so young people interested in learning an instrument were denyed because of the myth of these disabilities. The day after I received a plugin that put the names of the notes in teh notehead.
I was again dumbfounded to see that it became a part of the core of Musescore 3.x.
Since the developement of the plugin for Musescore 2.x I have introduced many clients and others to your program. The response and effort on the part of the programmers to include in the core program ability to put the names in the noteheads is something I will never be able to express my appreciation and gratitude to your inclusion of the aspect in Musescore 3.x. It has enabled those who were otherwise denyed access to playing a musical instrument access. I truly cannot express what this hase meant to me and so many others. Music is the internationsl language and has the ability to change someones life. I know this from my direct experience with so many yound adults and adults with reading disabilities. Thank you.
Clifton Willard MS, MS, MS, LPC/MHSP