Giovanni Pavolini <giovanni.pavolini@gmail.com> writes:

> I wanted to customize my default font by `(custom-set-faces '(default
> ((t(:family "Ubuntu")))))`. Then, after `M-x org-table-create` the TAB
> started creating a cell to the left of the one it should have jumped to
> (see a video here (webmd video of the screencast):
> https://u.pcloud.link/publink/show?code=XZVXhe0Z2K8AAQBKOwQH7uE7LkNtHYGlHQTy
> ). The expected behaviour is that TAB only jumps to the next cell,
> without creating additional ones. The actual behaviour is, depending on
> the family font used, it does create an additional cell. Not every
> font causes the unexpected behaviour.

[ Side note: we prefer text descriptions on the mailing lists. Videos,
  especially uploaded to third-party servers, may disappear after
  several years, leading to losing access to discussion context. Also,
  not every reader can access non-text information (consider blind users) ]

From the video the reproducer is the following:

1. emacs -q
2. Create a new Org file
3. M-x org-table-create <RET> 2x2 <RET>
4. a TAB table TAB a TAB table
5. Observe table filled with "a" and "table" cells

| a | table |
|---+-------|
| a | table |

6. M-: (custom-set-faces '(default ((t (:family "Noto Sans CJK HK")))))
7. Move point to the end of buffer
8. Repeat steps 3-4
9. Observe

| a |   | table |
|---+---+------|
|   | a | table |

I was able to reproduce using Org mode version shipped with Emacs 29.
I was unable to reproduce using the latest Org mode version.

May you please try to upgrade Org mode? Does the problem disappear then?

P.S.
Attaching the list of working/non-working fonts to keep it available for
future reference.