QGIS Vector Geometry Vanished

I’ve been working on a project, in QGIS 3.16 Hannover (we started the project a while ago, in the Bonn version, but upgraded during the duration of project). Upon project completion we’ve been asked to hand over the shape files also, not just the layout pdfs.

As it turned out, the last version of the shp is missing geometry of most attributes. The attribute table contains up-to-date state, but most of features now have no geometry, i.e. they exist as entries in the attribute table, but have null geometry.

Does anybody have a solution? Is it possible that this situation arose, because me and my colleague worked on the same project, often simultaneously? I.e. could it have happened because we inadvertently wrote over same shapefiles at the same time?

Also, what is the latest on archiving QGIS projects? Is there an automatic function available?

I guess I’ll live with the loss of data in this case, probably it’ll take me a day to recover (that is draw missing geometries by hand).