Iggrid "select all" works wrong when "load on demand" is used -> selects only first page records
Are you using igGridRowSelectors's select all functionality along with igGridPaging feature with type = remote?
If that is the case, the combination of these functionalities has limitations as follows.
Note: "Select All" functionality does not work for remote Paging. Clicking on the header checkbox will only select the rows from the current page.
Configuring Row Selectors (igGrid) - Enabling Selection across all pageshttps://www.igniteui.com/help/iggrid-configuring-row-selectors#select-all-pages