In 1.13.2, chests and trapped chests could be opened even if a shulker box was placed on top of it. In 1.14+ (including the current release 1.14.3), this is no longer the case.

This is likely due to lighting engine changes in 1.14. This change may be WAI, or won't fix, but it is not mentioned in any patch notes. Official clarification would be appreciated. 

To reproduce (See screenshot below for a possible setup):

1) Open Minecraft in 1.13.2

2) Place a chest/trapped chest.

3) Place a shulker box on top of the chest or trapped chest, using shift+ right click

4) Successfully open the chest/trapped chest.

5) Open Minecraft in 1.14.3

6) Repeat steps 2 and 3

7) Fail to open the chest.