overlapping disks after partition extension

The machine I'm working with runs Ubuntu 20.046 LTS and has two HDD plugged. The initial setup was following

I wanted to use sdb to extend ubuntu-vg-ubuntu-lv which would make a total of about 5.3T. Following advice from here I ended up with following situation:

and sudo pvs gives:

  PV         VG        Fmt  Attr PSize PFree  /dev/sda3  ubuntu-vg lvm2 a--  1.74t    0   /dev/sdb   ubuntu-vg lvm2 a--  3.49t 1.74t

which shows that /dev/sda3 is fully allocated although before following the steps it had some good 100G available. Digging little deeper I found viasudo pvs --segments that:

  PV         VG        Fmt  Attr PSize PFree Start  SSize   /dev/sda3  ubuntu-vg lvm2 a--  1.74t    0       0 457311  /dev/sdb   ubuntu-vg lvm2 a--  3.49t 1.74t      0 458240  /dev/sdb   ubuntu-vg lvm2 a--  3.49t 1.74t 458240 457311

So it looks like two resources start at 0 and if I understand this correctly - they overlap.

1. Is it possible to "shift" resources so there is no overlap? /dev/sdb was basically empty at the time of my attept to mount it.
2. Is there any safe way reverse this process or fix this? I check in lvm docs that it is possible to remove volume here but due to the overlap I'm not sure about the system stability.

If there are any other relevant diagnostics I can make on this - please do let me know. I'm happy to provide additional info.