For playdemo and normal gameplay the time float is correct on the first Draw() frame, this however isn't true for viewdemo, where it starts on the correct "server time" from that demo (e.g. 331) for a few frames, but then resets itself to 0 and starts adding up, this results in the 15 second offset for hiding the watermark message being set to e.g. 331 + 15 = 346, but time is then counting from 0, resulting in the watermark not disappearing for 346 more seconds when using viewdemo.