I tried to use environment variables for booleanNodes and get this exception:

In [BooleanNode.php](github symfony/symfony boolean node) line 29:
Invalid type for path "web_profiler.intercept_redirects". Expected boolean, but got string.

To reproduce the issue, I forked symfony demo and changed this:
https://github.com/sebastianblum/demo/commit/4df780b0fcfd593d3dbdac721f5ae32ae374367e

I extended the exception and the value was:
In BooleanNode.php line 29:
Invalid type for path "web_profiler.intercept_redirects". Expected boolean, but got string. Value was: %env(bool:APP_INTERCEPT_REDIRECTS)%

It looks like that the environment variables are not correct resolved for booleanNodes.