Have you tried sync/offset to 0, with focuser all the way in? Remember, it’s an off-set, so I the focuser thinks it’s at 0 (set during calibration with the primalucelab software), and you set an offset in the INDI driver of 30,000, then entering an absolute position of 0 would make he focuser move outwards to 30,000. I had the same experience when my offset for whatever reason was always showing up as 76k..something, the maximum travel of my focuser. Synching it all to the 0-position has alsways worked reliably.
Looks like Jasem already has updated the driver, so that may be a much better solution.

Using the last night build, I see some improvement as the last known focus position is correctly set when I use my Sesto Senso in a brand new Kstars/Ekos session. Which is great, thank you Jasem.
Unfortunately, a new bug has appeared (this is a regression compared to the last stable version I was using until today) : using the Indi Client board I have defined some preset values for that focuser. When I press the Goto button for one preset value, the Sesto Senso actually moves to that value, but that makes also the indi_sestosenso_focus driver crash. It is 100% reproducible. I attach the log file that shows the issue that is around these lines:

[2019-02-21T16:10:49.482 UTC INFO ][ org.kde.kstars.indi] - Sesto Senso : "[INFO] Device configuration applied. "
[2019-02-21T16:10:58.911 UTC INFO ][ org.kde.kstars.indi] - Sesto Senso : "[INFO] Moving to Preset 1 with position 0. "
[2019-02-21T16:11:00.113 UTC DEBG ][ org.kde.kstars.indi] - INDI Server: "2019-02-21T16:11:00: Driver indi_sestosenso_focus: terminate called after throwing an instance of 'std::invalid_argument'"
[2019-02-21T16:11:00.113 UTC DEBG ][ org.kde.kstars.indi] - INDI Server: "2019-02-21T16:11:00: Driver indi_sestosenso_focus: what(): stoi"
[2019-02-21T16:11:00.114 UTC DEBG ][ org.kde.kstars.indi] - INDI Server: ""
[2019-02-21T16:11:00.310 UTC DEBG ][ org.kde.kstars.indi] - INDI Server: "Child process 6843 died"
[2019-02-21T16:11:00.310 UTC DEBG ][ org.kde.kstars.indi] - INDI Server: "2019-02-21T16:11:00: Driver indi_sestosenso_focus: stderr EOF"
[2019-02-21T16:11:00.310 UTC DEBG ][ org.kde.kstars.indi] - INDI Server: "2019-02-21T16:11:00: Driver indi_sestosenso_focus: restart #1"

Ok I pushed a possible fix to GIT. Can you recompile from GIT and test?

Hi Jasem,

I have recompiled the whole indi code from git. It contains your latest changes ( 003601f6b1a79a1f20efba273cb090b4eb51806c, f937d764ac4d494ede5f3c1860a23a6689a2d5ed, etc) for the sestosenso.cpp file. But unfortunately these changes do not fix the issue, any press on any preset button makes the driver crash.
I attach a log file that contains 2 successive crashes.
Sorry for the bad news.

Problem it crashes before debug is enabled. Please edit your profile and turn off "Auto Connect". Then start the profile and make sure the debug logging is turned on in the SestoSenso driver, THEN press Connect and hopefully the log would be useful. Or just send me TeamViewer details and I'll check it out.

I did what you suggested, made 2 trials and got 2 debug files. They do not seem to be very informative, despite I entered the 'sync' command from the terminal in order to flush any buffered information.
For security reasons, I do not have an Internet access on my astro set-up. So no vnc or similar software.

Ok I added error -checking code so at least it won't crash now. Please git pull and report back.

Dear all,
thank you very much for the support!

Jasem, I am now at home again and I will download the latest build. If it is helpful you can have access to my Laptop. Furthermore I will be available the whole weekend. So if you want and it is helpful just tell when you want to get access via TeamViewer.

OK, I think you have caught the bug. The SestoSenso firmware sometimes returns some 0-byte position value while it is fast moving. Attached are 2 log files, one with a 100 ms polling period, the other with a more reasonable 500 ms period.
Thanks a lot for your support, Jasem.

Thanks for the test. I believe I found the issue.. this is specific to GOTO presets. It wasn't setting the absolute position property status flag properly. Can you git pull and recompile again? Thanks!

Thank you Jasem and Dahu for the support!

I have downloaded the latest build and want to test it but now I have another problem: Ekos does not recognize my camera (DSLR) and my guider (ZWO ASI). I am sorry, but i am a relativliy beginner and i do not know what i am doing wrong. I added a logfile. Thank you!!

Jasem, I have git- pulled and recompiled, and the 0-byte warning messages have vanished, it seems you've got it. Just great.