Ticking command blocks not updating when joining or importing a world.

Hello,

I have a problem with some ticking command blocks that are not running when I join, or when I Import my world from a .mcworld.

All the blocks are placed in a ticking area.

These blocks are in always active mode, but I also tried in need Redstone mode. 

The only way that I found to restart these blocks is to put them in Redstone mode, and to remove and place again the redstone block. But it is still breaking sometime when I save and quit, and always when I export to mcworld.

Also, on the screenshot i sent, the LastExecution value is not changing. On the working command blocks, it is changing.
 

Thank you in advance for your time and your help.

Thomas