When the first columns are small and the last columns are wide the grid does not render all the visible columns in the grid.
Wen the first columns are wide and the last columns are small the last columns will not de shown.
The problem can be reproduced when you open https://snippet.dhtmlx.com/pcnicbd5 on a window with a width of 2000 pixels. (the grid will be 811 pixels wide)
We have fixed your reported problem in the latest (v.7.3.6) update of the dhx.Grid.
You can test it in your original snippet.
Please, try to download the latest available dhx.Grd/Suite build from your client’s are to get that fix.
Thank you for your report and patience.