LUBA 3: leaves 90-degree corners unmown, or swings wide round them

What owners report

• A new LUBA 3 owner watched the mower and found areas around the perimeter that never get mown. Where there are sharp turns on a perimeter run, the mower does not try to follow the perimeter at all¹. The owner was using the standard obstacle avoidance mode².
• Another owner in that thread says 90 degree corners are not done unless obstacle avoidance is turned off, and that with it off the mower gets closest to barriers³. A LUBA 3 owner replying in German says that switching off the obstacle detection made it work, though it has got a little better with the last update⁴.
• A LUBA 3 owner in a German forum, who had a LUBA 2X AWD before, says a plain right-angle corner is left standing in about three places in the garden and the mower even drives round it on purpose, with AI switched off⁷. He sees it when the mower turns right at a right angle. A second owner says the same, and thinks it is because the LUBA 3 no longer stops at the corner and realigns as the LUBA 2 did, but drives through in one go⁸.
• A third forum owner says everything was fine on firmware 2.3.30.26, then the mowing got worse: unmown patches, no clean passes round no-go zones, and the blades switched off where it makes no sense. The mower used to go cleanly round corners; now it stops, switches the blades off, reverses, goes forward and waits, then takes a big arc round each corner and leaves grass standing⁹. On 3 November the owner wrote that photos, videos and logs had gone to Mammotion again, that Mammotion had been in contact since 7 September, and that the last update changed nothing¹⁰. A fourth owner in that thread says the same, and that it was not like this from the start¹¹.
• A LUBA 3 AWD owner in a second forum thread bought the mower in spring and says it was good at first, then worse since about June and several updates. Outside corners are taken so widely from one driving direction that grass is left standing¹². At inside corners the mower switches the blades off, positions itself well, then switches them back on much too late¹³. The owner suggested to Mammotion that the perimeter direction change at the start of each task, so a corner is not always approached from the same side, and says the replies were promises that the problems would be passed on or improved in coming updates.

What Mammotion said

On 1 September a Mammotion staff account asked the first owner which obstacle avoidance mode the mower had been using and whether changing it would help. It suggested adding an obstacle-free zone to the area the mower missed, and said this is usually quite effective⁵. A second staff account answered the same owner that Mammotion will keep optimizing how closely the mower follows the perimeter⁶. Neither reply names a firmware version or a date.

What we do not know

• The cause. One owner links it to obstacle avoidance, and another still has it with AI switched off. Mammotion's replies do not say.
• Which firmware began it. One owner gives a version where it was still fine, 2.3.30.26. The others say only that it got worse after updates.
• Whether a setting cures it. Owners say turning obstacle avoidance off helped them. Nobody reports that an obstacle-free zone worked.
• A fix. No source says a firmware release is aimed at it.

Not the same as

Bare, torn strips where the mower turns are on their own page. A mower swerving round a few leaves or low plants is on another page. The same first thread also complains that the app draws a skipped area as mown, which this page covers.