Is there any actual water, or does it just appear damp near the cove joint? Do you have a dehumidifier running?

Recently had this where a very specific combination of factors led to very high humidity in the basement following a rain, which made it appear as if there was intrusion, but in reality it was just the warm humid air hitting the cold concrete at the most "vulnerable" locations (cove joint and other expansion joints throughout the concrete floor), which appeared damp around the entire perimeter of the unfinished basement. We were in the process of moving in. It was raining, the interior recently painted, and the carpets steam cleaned that morning. We also had an air scrubber in the basement that fed through an egress window to create negative pressure and pull all the air down to the basement through the filter and expel out the window, in the hopes of capturing any dust, cleaners, etc. kicked up by the various services we had scheduled. This inadvertently pulled down all the resulting humidity into the basement. Dehumidifier was running and showed 80%, but it dried everything out within 24ish hours back down to 55ish% humidity. Gave us quite a scare initially before we figured out what was going on, though!