Major INDI Library release v1.9.0 bring significant internal changes championed by @pawel-soja to modernize core INDI Library drivers and clients. New drivers for DeepSkyDad Flat Panel & Pegasus devices plus further improvements to PCM8 drivers.
Sesto Senso 2 always resets to 0 focuser position when I disconnect from Ekos.
It's supposed to remember last position AFAIK. I just updated the driver to fix a small issue that might cause what you experienced. Driver v0.2 is pushed to GIT and should be available in nightly later tonight.