Cicode on page does not work with external tag

SCADA works in the following configuration:

PLC S7-300 => Simatic NET OPC-UA Server => Citect 2018(v 8.10) 

I/O Device configuration:

 There is a button with not working code on the page:

OnUp      =>     TAGNAME = False;

OnDown  =>    TAGNAME = True;

Enabling Background Poll (Rate = 00:00:01) does not affect for this.

If I place any animation with TAGNAME on the page, the button begin working.