I should probably set my tags to slow mode. I have six running with RuuviCollector (installed with the Ansible playbook). RSSI -70 to -100.
I installed the last one today on the north wall to get outside. It is probably near the limit of what is recievable with default settings (1 measurement/s). I made a little 3D printed case that hopefully keeps the woodpeckers out. Oddly the signal seemed to improve as it cooled to the outside temperature. The dew point is a but suspicious. The humidity measurement may take a bit longer to stabilize.
Anyway, I reread your original post and noticed that it was all or nothing so not a problem with a single sensor or signal strength.
I am using a Pi3B without a screen.which is most likely using one of the “lite” raspbian images. I haven’t encountered anything power related, but I haven’t installed many extra packages beyond what was necessary to install Ruuvi Collector with Ansible.
Maybe /var/log/kern.log may show something you can correlate to the lack of data.
Could also try disabling screen blanking with raspi-config and see if that makes a difference.