xmap caching method recreating the xmap object

### Version

main

### Are there any linked Issues or Pull Requests?

#276

### What happened?

There was a bug in the `generate_redistribution_map` code. Even if the `xmap` object is already created, the code overwrites this object and creates a new `xmap` object. This pull request fixes this bug. 

### Relevant log output

```shell

```