I purchased a Stowa Flieger (no date or logo) from a forum member. I love the watch and it works very well in terms of precision. I recently noticed that there is a very subtle "click" sound on every 1-1.5 full rotor turns when I swirl the rotor (like what a watch winder is doing). This repetitive "click" is happening regardless if the watch is fully wound or not, or if the the rotor spins very slowly or fast. I am wondering if you guys have the similar noise as I do. According to the website, the movement is ETA 2824-2, with blued screws and B-Uher rotor. Any information would be greatly appreciated. Thanks.