As shown in the video, a simple plus sign layout of slime blocks on top of a vertical piston attached to a simple clock can cause weird rendering issues with moving blocks (in this case, wool).
Linked issues
relates to
Attachments
Comments
Still occurs on default texture pack, as attached to the original issue.
Confirmed.

Can confirm with blue wool only, no other block will show that. Maybe related to MC-54053

Is this still a concern in the current Minecraft version? If so, please update the affected versions in order to best aid Mojang ensuring bugs are still valid in the latest releases/pre-releases. If this has been done, we can reopen the issue.
Keep in mind that the "Resolved"-Status on this ticket just means "Answered", and that we are waiting for further information on whether this issue still exists or not. We will reopen it as soon as the requested information has been delivered.
Ticket resolved as incomplete, because no answer in a reasonable amount of time (1+ year), if it still happens, please update the ticket.
You are playing on what appears to be a broken resource pack. Please test this again on the default texture pack, and see if it occurs there.