Dry glue from floor???

[Tentontousand]

So I lifted up our rug/antislip rug thing and we see this (see attached image)

Any know why the hell glue is appearing between these kardean style floor boards? I never see the glue wet only dry and chalky. The floors were installed way before we even moved in. Very confused.

 

[crazydaze]

Does it wipe off?

 

[Tentontousand]

Does it wipe off?

I've got to scrub it off

 

[foxhole]

In bathroom ?

 

[Tentontousand]

In bathroom ?

Nope it's in the living room at the front of the house. So weird...