The ends of two signs placed next to each other do not touch. The width of the sign is less than one block. In Java Edition, signs have the width of a full block.
MCPE-159442
Sign width is less than a full block
Open
1
(Unassigned)
835031
Confirmed
Multiple
Xbox Series X latest update as of 2022 July 20
1.19.20.23 Preview, 1.19.10
Retrieved
This is cool sometimes, but also annoying when you're using signs to make a boarded up door. You can't have a boarded up door WHEN THE BOARDS HAVE GAPS IN THEM.