Move the table scroll line left and right, the table content can move normally, but the table title

lake

question： Based on iframe, functions: fixed header, fixed columns,Drag left and right to the scrolling row of the table will cause the table title to get stuck.
Environment: **Firefox browser (80.0.1 (64 bit), using the latest version of DataTables
**Description：
- Start the debugger with F12, select event listener breakpoint->control-> scroll event breakpoint
- Scroll bar in advance, the first time there is no problem, but after the title is stuck.
PS:Normal use, occasional
demo：
1. See attachment
2. question