Attached is a sample project.
Follow the instructions in the comments to see SE insert an 'a' character after the '<':
#include <iostream>
int main(int argc, char **argv)
{
// Put cursor just after the t in std::cout
// press <space> then a single '<' character
// SE inserts an 'a' character after the <
// such as: std::cout <a
// If you don't see it right away, try closing/re-opening SE a few times
// If you do this with an empty config, after pressing the <, then it tags gcc
// after tagging is completed, backspace to after the 't', then do:
// "space""<", and you will
// see the <a
// Often when I type the second < and then space, I end up with:
// std::cout <<a
// but it doesn't seem to happen in this small test project.
// This issue occurs in SE 21.0.3 also
std::cout
// This is what I see after typing ' <'
// std::cout <a;
return 0;
}