Hi, I'm a developer of Fusion joints. Thanks for the informative video. I cannot completely diagnose the issue without the model, but I can shed some light on what is probably going on here.
The "conflict" errors arise when joints restrict positioning in conflicting ways. For example, a component that is a box can be rigidly fixed to two grounded components (or bodies in root component which does not move). This can solve as long as the component has certain dimensions. When these are changed, the joints are pulled apart and cannot solve the system. The good news is that this is probably not a Fusion bug. It is a case where a redundantly constrained system was changed by the sketch edit, causing a real conflict. If so, this can be fixed by you.
This circumstance happens when you have a loop of joints. A loop can be needed (example: a four-bar mechanism) but they can be introduced by accident, making the assembly prone to conflicts. Ground components function as a single unmovable component, so these loops can occur unexpectedly when attaching components to ground and each other. Fusion will warn when adding a new joint will cause a conflict, but in your case, the conflict did not happen until you changed geometry later. Removing unneeded loops will make this problem less likely. A good Fusion enhancement would be to help identify these loops.
All CAD systems with assembly constraints will have this problem, but Fusion offers an interesting way to solve it. To resolve this, a good practice is to look at the first joint or snapshot feature in the timeline that has a conflict. Fusion uniquely adds kinematic joints and snapshots in a linear feature history, so you can go back to where the problem started after the geometry change and look at the model before it becomes more complex. Once there is a conflict, later joints and snapshots will also complain of the same conflict. It may be that there is just one conflict to resolve that results in a lot of noise.
It is interesting that the revolute still works even though there are conflicts in other joints. This indicates that your mechanism has multiple independent joint systems which can fail individually without locking up the others (another thing Fusion can do). Grounded components tend to isolate systems. For example, two doors attached to a grounded wall are independent systems sharing the same (grounded) component. When a system has a conflict, it is frozen -- no joints in that system will move. The first failure in your model is in the cylindrical joint cyl6. The edit to the sketch probably caused a kinematic loop of joints to not be able to assemble. The Cyl6 closed the loop and is therefore marked as in conflict.
The best way to fix this is to look at the system of joints that includes Cyl6. You can move the timeline marker back to just before the Cyl6 joint or just after. Is there an unnecessary joint that is overconstraining the system? How does the geometry change affect this system? Editing one of the joints to change its type (degree of freedom) or select different geometry can resolve the problem. If there is an unnecessary loop of joints, deleting one might be the solution. You can temporarily delete a joint by suppressing the feature in the timeline (right-click on feature in timeline and choose Suppress Feature).
Also, joint occurrences can be suppressed individually by right-clicking on the joint in the view or browser -- but I don't think that helps you . A joint definition may have multiple occurrences (e.g. a piston cylindrical joint in a multi-piston engine assembly has multiple occurrences -- each with its own position). These occurrences can be suppressed to help diagnose conflicts. To make a joint be suppressed at a specific point in history, you need to move the timeline marker back to that point in history, suppress the joint occurrence, and save the suppression in the timeline as a snapshot. It is simpler to just suppress the joint feature. [Edit] Another way to avoid loops is to unground a component.
A final suggestion for now: you can use the "as-built" joint type when the joint's components are already in assembled positions due to earlier features in the history. This type of joint is much more ammenable to geometry changes earlier in history because it does not try to match up two separate geometries that might be pulled-apart by a geometry change. The "as-built" joint accepts the joined components as they are and defines the joint. Use as-built joints as much as possible when components don't need to be moved into an assembled position by the joint.
If this helps, please let us know. If not, please provide the model shown in the video and I can give you more specifics.
