Opening documents - LibreOffice app starts and hides

I have a document/database application where I select the document to open. The app saves it from the database to the file system and then executes it. I have several applications for opening documents/media, like LibreOffice, PDF-XChange Editor, IrfanView and VLC. Opening the files works flawlessly for any kind of file associated to any program except for those opening in the LibreOffice.

LibreOffice just starts (the splashscreen appears and closes) and then nothing happens. A look into the processes via Task Manager shows that both LibreOffice and Writer or Calc processes are running, but somehow hidden and inaccessible.

Has anybody come across similar behaviour?

Any suggestions are much appreciated,

Tomaž

What is the command used by the database program to open the file?
In task Manager are the LO processes in Background Processes?

It’s a Delphi app executing the file (once it is unpacked from the database to the file system) by a RunAndWait command. As I mentioned above, it does not seem to be problematic as any other files (PDF, BMP, PNG, MOV, MP3, etc.) open in associated program with no issues whatsoever.
The machine is a WS2012R2, the LO is v5.0.6.(x86). The three processes initiated are indeed all background processes: LibreOffice (twice) and LibreOffice Calc (once) PIC