Merged segments have disappeared permanently

Question

Hello, 
 I merged several segments and then realised it was a mistake. I wanted to undo the manipulation but it was impossible. I then followed the procedure www.trados.com/.../how-to-merge-segments-across-hard-returns-in-sdl-trados-studio.html to make the merged segments appear. 
 But I don't understand why some segments have disappeared since then. Nine segments no longer appear. 
 This creates 9 offset errors and causes problems in editing the final document. 
 Does anyone have an idea please? 
 Thank you very much!

Paul · Answer

Sébastien Couppey 
 Jerzy is correct. There is no way to undo a segment merge like this but the good news is that it should be simple to recreate the project and pretranslate if you created the project yourself?

Trados Studio > 1. Trados Studio

Merged segments have disappeared permanently