Found it.
Here it is definitly
space is denoted by "_"
Item_
Data
Item2_
Data

hload that
//echo -a $hget(table,item)
shows: nothing
//echo -a $hget(table,item_)
shows: nothing
//echo -a $hget(table,item $+ $chr(32) $+ )
shows: Data

This may or may not be a bug
You decide