What version of the PI ProcessBook was used to save the display in question? If the version of PI Processbook is prior to the 3.3 version, then this behavior may be expected.
When the display is saved in ProcessBook version 3.3+, it uses the local settings to create a codepage, which is then associated with the display.
Now that there is a codepage associated with the display, Vision can look at the codepage instead of the Vision server's local settings, and it displays the correct characters.
Re-saving the display with the newer version of ProcessBook should work.
Note that the client machine where you will save the display in PB 3.3+ must match the settings the display was created in.
Otherwise, the display would not show the correct characters, and saving would not fix the issue because there is nothing for PB to build an accurate codepage out of.
For more details you can check following article: https://techsupport.osisoft.com/Troubleshooting/KB/KB00993/
The version of the PI ProcessBook is 3.2 .
Note that there is a known issue where if you create a display in ProcessBook 3.2 in one code page and then you re-save it on a machine that has a different code page, you can end up with garbled text on the display. This actually happens more than you might think ... It happens often enough that Tech Support has a utility available to fix these displays.