I purchased my Pixel XL from Google back in December and have had constant signal dropping/signal loss issues since day one. Examples..
1.) About 25-50 times a day my phone will completely drop/lose signal and I will get a hollow triangle in the signal/bars icon in the notification bar. After about 30-60 seconds it will reconnect. Sometimes it will stay connected for a good while after this, other times it will repeat this process 5-10 times until it gets somewhat stable.
2.) 25% of the time I lose signal like this I will get a "no sim card error" when this happens I have to power cycle my phone otherwise it will never reconnect.
3.) A lot of the time, I will experience this immediately after receiving a text, as a call is coming in, or if I'm placing a call, immediately disconnecting me. When this happens as a call is coming in, it will ring once, my phone will lose signal, and on top of that my phone doesn't even show that I missed a call so unless I catch the number or who is calling me. If i don't, I have no idea who it was that tried to call me or don't ever get notified that someone did in fact try to call me.
3.) I know within a 25 foot radius numerous locations around my town where the signal will drop. Also at my house, it is constantly happening. If i walk to my bathroom or to my office, boom signal drop.
4.) Everytime the signal drops, my voicemail gets deactivated. Yes that's right deactivated. As in I don't have a voicemail. The voicemail tab in the dialer/phone app disappears and I have to manually toggle it off and back on for it to show up. Meaning if someone calls me and my phone drops signal, or if they try to call while my phone is in the process of dropping signal, my phone will not display a missed call and on top of that, they can't even leave me a voicemail.
5.) My wi-fi calling also disables everytime my signal drops. I have to constantly re-enable it to the point if I have wifi, I've gotten in the habit of turning on airplane mode, enabling wifi, and then turning on wifi calling.
6.) when the signal drops, I can't even dial out to 911. Imaging a burglar robbing my house and me telling him if he can hold on a second while I power cycle my phone so I can dial 911.
I've been RMA'd a new pixel and still have the same issue. Tier 3 verizon support said it wasn't a network issue on their end. Which i don't think it is anyways since I've been with Verizon for 10 years, in the same town, having numerous devices during that time span and have never had this issue. Google support refuses to issue me a refund, they have no possible fixes or suggestions and refuse to work with Verizon at all. A direct quote from the team lead I talked to earlier, "all we can do is file an RMA for you". When I asked what is the course of action if my 2nd replacement pixel has the same issue his response was, and I kid you not, "we would ask for you to file an RMA".