Glazed terracotta can't be pushed by branched slimeblock

Piston don't extend when get activated while trying to push terracotta not directly infront of it (using slimeblocks).

• Happens both for sticky and non-sticky piston.
• Distance from terracotta to piston doesn't matter, nor does direction.
• Also piston can't move terracotta infront of it if between the piston and the terracotta is at least one block, that will break when pushed and will not push any blocks (e.g. air, button, cake).

Is this a bug though ?