world partition problem in ue 5.3

i have a big problem for a project in which i used world landscape partition map.
everthing was good but after making a BP with pcg and created by it a packed level actor, during saving of the packed level actor the system said errors

and it seemed that working but after a while on saving the map, the project crashed and after reloading the project the landscape was distrupt, no more LandscapeStreamingProxy, i had 81 in outliner before and on reloading 80 disappeared.
it was not possible to rebuild the 80 LandscapeStreamingProxy.

why?
are there a solution to rebuild the landscape proxy i had?

where are saved?

i think that there is a bug between bp with pcg and packed level actor

please let me know…

i forgot all my landscape!!!