With "/ps off" a player can't place a normal diamond block (or other pstone-defined block) down without getting the "Cannot place field here message" because there is a nearby field that would conflict if he were actually placing a pstone. Normally he should be able to place the block down as a standard diamond block. This could be a problem for people that use somewhat more mundane custom blocks that players are likely to place a lot of.

Once outside of where the field would conflict the player can place the block as normal and it registers as a normal non-pstone enabled block as it should. It seems the check for conflicts isn't considering whether or not pstones are enabled.

Using CB1240 with PS 6.4

fixed