executing org-table TBLFM form changes (resets) language settings

[Rainer Stengele <rainer.stengele@online.de>]

All,

My current-language-environment is "German".
Having an Org table with a TBLFM attached:

| IM Startzeit          | IM Endezeit           | Stunden | delta(x,16) | Anm. |
|-----------------------+-----------------------+---------+-------------+------|
| [2018-01-22 Mo 19:30] | [2018-01-23 Di 14:30] |   19.00 |        3.00 |      |
|                       |                       |         |             |      |
#+TBLFM: $3=24*(date(<$2>)-date(<$1>)); %.2f::$4=$3-16.0; %.2f

entering a new timestamp correctly inserts German dayname abbrevs: ("Do", German for "Thu", English):

| IM Startzeit          | IM Endezeit           | Stunden | delta(x,16) | Anm. |
|-----------------------+-----------------------+---------+-------------+------|
| [2018-01-22 Mo 19:30] | [2018-01-23 Di 14:30] |   19.00 |        3.00 |      |
| [2018-01-25 Do 14:19] |                       |         |             |      |
#+TBLFM: $3=24*(date(<$2>)-date(<$1>)); %.2f::$4=$3-16.0; %.2f

Executing the TBLFM line with C-c C-c changes (resets) the language environment to English.

Now inserting a timestamp inserts "Thu" instead of "Do", that is it uses the English day name abbrevs:

| IM Startzeit          | IM Endezeit           |      Stunden |  delta(x,16) | Anm. |
|-----------------------+-----------------------+--------------+--------------+------|
| [2018-01-22 Mo 19:30] | [2018-01-23 Di 14:30] |        19.00 |         3.00 |      |
| [2018-01-25 Thu 14:21]|                       |              |              |      |
#+TBLFM: $3=24*(date(<$2>)-date(<$1>)); %.2f::$4=$3-16.0; %.2f

Believe me it took me some time to find out what action in Emacs changes the whole lang environment.

Is that a bug or is there a language setting in the TBLFM form?

Thanks for any hint.

Regards,
Rainer