The shortest way to explain my issue is this -
In GA4, under the Conversions report, if I add a second comparison that is identical to my first comparison but additionally specifies a page path, the counts for Conversions and Total Users change for the base comparison. (A similar phenomenon happens in the Landing Page and Events reports.)
For example, with only one comparison (Comparison A), the conversion count is 10. If I add a comparison (Comparison B), the conversion count for Comparison A is now 7 and the conversion count for Comparison B is also 7.
I am confused about why the count for Comparison A changes as the parameters have remained the same.
Further details-- I have played with three comparisons total while troubleshooting this: Comparison A: All Users; Comparison B: First user source/medium includes XX/YY, First user campaign includes ZZ; Comparison C: First user source/medium includes XX/YY, First user campaign includes ZZ, Page path and screes class includes WW
**There is no difference between Comparison B and C other than the addition of "Page path and screes class includes WW"
If I use Comparison A + Comparison B, Comparison B says there are 10 conversions for Red Button Clicks.
If I delete Comparison A (All Users), Comparison B still says there 10 conversions for Red Button Clicks.
If I add Comparison C to Comparison B, Comparison B now says there are 7 conversions for Red Button Clicks. Comparison C also shows 7 conversions for Red Button Clicks. These numbers remain the same if combined with Comparison C (All Users).
My theory is that this is a glitch, but if it is not, I would love to know what the logic is behind it.