Have same problems..
I have the exact same problems and without any cover or screen protector. Have had droid for a week and have probably been able to make one call properly during that time. Sometimes, I hang up, sometimes I start a conference call with my voice mail, or someone else, and sometimes it mutes me. My droid also likes to dial some random numbers for me. I recvd the 2.1 update over the weekend and the problem has stayed.
The sensor works if I put my hand over it. But sometimes and not always when I am in call.
After searhcing thru the forum, I found the hair being the reason for the sensor acting funny. And yes, I am a girl with hair just touching to my chin.
Personally, I find this solution of moving the hair away unacceptable. The phone is supposed to work for me and make my life easier.. not the other way round. And, about holding the phone a certain way, how do you stay focussed on keeping the phone aligned a certain way when if you are talking on the phone while doing something else.
I am sorry for venting out like this. I feel extremely disappointed by the phone. Ever since getting the phone, I have spent 2-3 hours a day on this forum (yipee!) trying to find solutions for all the various problems I am facing with the phone. Some have been solved - some not. This one is a bi sticking point though.
If anyone has any experience with the app mentioned earlier that will lock the screen during call, please let me know. eg: how do you unlock the screen once it gets locked.
I feel like I am going from "droolingondroid" to "pukingondroid". I was hoping for a better experience from a google/moto phone. I haven't yet been able to enjoy the phone to allow its good features to sweep me off the floor. I am still dealing with all the issues.. starting from getting gmail to work on it. (thats been miraculously fixed).
Anyways, that was cathartic and felt good. Thanks for reading! and of course, any fixes (to the phone) are more than welcomed.
Probably was that screen protector of yours