I have an old Monoprice Select Mini Pro (v3) that has sat for years. I got it out today to see if it still works and it does. It printed fine the last time I used it but I’ve gotten bigger and better printers since then. However I lost the slicer profile I was using and decided to start from scratch with Orca. I just plugged in the dimensions and changed some start g code for the initial purge line as the default was going well off the bed. I also tried changing the retraction distance to 4.5 because this is a bowden tube which did not change this issue. The initial purge line and outer perimeter of the first layer stick really well but the middle infill is blobbing at one end and stringing through the middle and not sticking to the bed at all. I have been playing with the z height end stop (the level sensor is bad so I had printed an adjuster for the z end stop) to adjust the initial layer height and I’m pretty sure I went from too high to too low facing the same issue. I know it’s not the filament because it’s a new spool that I just printed on another printer with yesterday. I’m leaning towards it being a slicer setting of some kind having to do with the extrusion, I’m just not sure which setting it could be. Thanks for any help.
Edit: well the z axis motor just died because I lowered the z axis too far and it hit the bed and it was acting funny earlier so that’s probably the issue.
My experience of this is that is because Cura over extrudes the walls deliberately to help adhesion and strength - I want to say the setting is called “overlap”. It’s the one where the infil runs into the walls a little bit to tie together the edges, but that’s always going to result in a bit more plastic being laid down in those areas.
Normally it causes a bit of a brim to cut off, but in your case it might just be enough to let it stick round the brim but nowhere else.