Spreadsheet: number format changes unintended

This issue is unique.

• I have used the search tool and did not find an issue describing my bug.

Operating System of DocumentServer

Docker

Version information

8.2.1.38

Expected Behavior

Number format of a cell sticks to definition

Actual Behavior

Number format of a cell changes unintentionally to date

Reproduction Steps

Example 1

1. In spreadsheet app
2. Select a cell
3. Set Number Format to fraction
4. Enter data '.5' -> '1/2'
5. Enter data '1/2' -> '1-Feb' / Number Format now date
6. Enter data '.5' -> '0-Jan' / Number Format still date

Example 2

1. In profile change language to Deutsch (Deutschland)
2. In the spreadsheet app:
3. Set Number format to Number (Zahlenformat: Zahl)
4. Enter data '0,5' -> '0,50' / formatted as number
5. Enter data '0.5' -> '0,5' / formatted as text
6. Enter data '1.5' -> '1-Mai' / formatted as date
7. Enter data '0.5' -> '1-Jan' / formatted as date

Additional information

Operating System of DocumentServer unknown, entry forced by mandatory field

Start by running the spreadsheet reproduction steps in the issue, including the German locale case, and compare the selected number format with the displayed result after each input. Done means fraction and number formats remain selected, and inputs such as 1/2, 0.5, and 1.5 are not unintentionally converted to dates or text.