['Bubble' lines, a Cura settiings issue?]

I had the exact same issue, and I noticed that if I immediately printed again then the print was perfect.  I think I had skin oil on the BuildTak surface I was printing on which caused localized severe adhesion issues.  Maybe try a quick back to back test?

 

For me: I was printing .2mm high by Xmm by Ymm flat squares to test ABL.  I noticed that my first print after messing with the build surface would have that issue, and initially I thought maybe the print head was high or my leveling mesh was wrong... but then I noticed that without changing anything the next identical re-print would be perfect.  Things would stay perfect until I enlarged the square or moved it and I might see the issue again.  Now I'm just really careful with the surface and I don't see the issue very often.

 

HTH

[Will Cura ever come to IOS?]

Someone has actually started that process:

 

It's buggy and incomplete right now, but a really interesting start.  And as someone who likes Shapr3D and Octoprint.. I would love this...

[OctoPrint Plugin - Ender 5 Plus Z-Axis Reversed in Monitor]

I'll just add that I just found this happening to me on my Ender 5 Pro and google helpfully led me here. 😃 Please count me as another person who would love to see independent axis (re)inversions as an option for the Cura-Octoprint interface.  Thanks for the amazing work on the plugin, it is impressively slick...