This is a partition layout that may lead to problems with manjaro. You can’t rollback securely this way !!!
Why ?
Your /boot is on another partition then your / . When you update your system, the kernel will be updated at the same time.
on / you will have all revisions of all the different modules for all kernel-versions you need to rollback
on your /boot every kernel-version will replace each other. you really only have the newest kernel-version there !
When you roll back then there is a kernel in /boot with his new initramdisk.
BUT
later in the boot-process this new kernel will not find its own modules. because you rolled back / into an older snapshot.
I don´t know if this is the problem you face at this time. But i got burned. 
So i learned: With manjaro you have frequent changing kernels. To do a save rollback you can’t have /boot as extra partition. This used to be a good idea years ago. but nowadays it is best to not have /boot as partition