Sysupgrade/jffs2 again: looks like serious bug

I have ZBT we826 (16MB flash), and a custom built image from latest trunk shows following error after first boot:
Tue Feb 25 14:40:08 2020 kern.warn kernel: [ 364.978406] jffs2: Erase at 0x00c12000 failed immediately: errno -22

And later on, file system is corrupted.
I.e. multiple
: kernel: [ 5127.301405] jffs2: Node CRC ffffffff != calculated CRC f09e7845 for node at 00c08510

There are similar problem reports here, using other devices. Just search for "jffs -22"

Will file bug report

I am getting the problem after any random number of reboots my JFFS2 overlay is lost and i get a bunch of error while rebooting in the serial console
[ 353.498856] jffs2: Node CRC ffffffff != calculated CRC f09e7845 for node at 000c10d0
[ 353.506850] jffs2: Node CRC ffffffff != calculated CRC f09e7845 for node at 000c10d0
[ 353.514858] jffs2: Node CRC ffffffff != calculated CRC f09e7845 for node at 000c5ac0
[ 353.522868] jffs2: Node CRC ffffffff != calculated CRC f09e7845 for node at 000c10d0
[ 353.530829] jffs2: Node CRC ffffffff != calculated CRC f09e7845 for node at 000c10d0
[ 353.538811] jffs2: Node CRC ffffffff != calculated CRC f09e7845 for node at 000c5ac0
[ 353.546802] jffs2: Node CRC ffffffff != calculated CRC f09e7845 for node at 000c5ac0
[ 353.554811] jffs2: Node CRC ffffffff != calculated CRC f09e7845 for node at 000c10d0
[ 353.562821] jffs2: Node CRC ffffffff != calculated CRC f09e7845 for node at 000c5ac0
[ 353.570782] jffs2: Node CRC ffffffff != calculated CRC f09e7845 for node at 000c5ac0
[ 353.578766] jffs2: Node CRC ffffffff != calculated CRC f09e7845 for node at 000c10d0
[ 353.586780] jffs2: Node CRC ffffffff != calculated CRC f09e7845 for node at 000c10d0
[ 353.594791] jffs2: Node CRC ffffffff != calculated CRC f09e7845 for node at 000c5ac0
[ 353.602803] jffs2: Node CRC ffffffff != calculated CRC f09e7845 for node at 000c10d0
[ 353.610764] jffs2: Node CRC ffffffff != calculated CRC f09e7845 for node at 000c10d0
[ 353.618745] jffs2: Node CRC ffffffff != calculated CRC f09e7845 for node at 000c5ac0
[ 353.626737] jffs2: Node CRC ffffffff != calculated CRC f09e7845 for node at 000c5ac0
[ 353.634746] jffs2: Node CRC ffffffff != calculated CRC f09e7845 for node at 000c10d0
[ 353.642764] jffs2: Node CRC ffffffff != calculated CRC f09e7845 for node at 000c5ac0
[ 353.650727] jffs2: Node CRC ffffffff != calculated CRC f09e7845 for node at 000c5ac0
[ 353.658709] jffs2: Node CRC ffffffff != calculated CRC f09e7845 for node at 000c1