When examining some problems with my ProOrder code, I found some very strange behaviour using the ONCE statement. I have shortened those problems to some demonstrative examples.

First example:

once i = 0
if i = 1 then
   buy 1 contracts at market
else
   sellshort 1 contracts at market
endif

Expected behaviour: Generating only short orders.
Real behaviour: Generating only short orders.
That is ok

Second example, adding the line i = 1:

once i = 0
if i = 1 then
   buy 1 contracts at market
else
   sellshort 1 contracts at market
   i = 1
endif

Expected behaviour: First should be a short order, after that only long orders.
Real behaviour: Generating only long orders.
That is not ok. Why is the first sellshort statement skipped although i is not equal to 1?

Third example, adding the line i = 0:

once i = 0
if i = 1 then
   buy 1 contracts at market
   i = 0
else
   sellshort 1 contracts at market
   i = 1
endif

Expected behaviour: Alternating short and long orders, starting with a short order.
Real behaviour: Alternating short and long orders, starting with a short order.
That is ok again.

Fourth example, something with a counter:

once i = 0
if i < 3 then
   buy 1 contracts at market
else
   sellshort 1 contracts at market
endif
i = i + 1

Expected behaviour: First 3 orders are long orders, after that only short orders.
Real behaviour: Generating only long orders
That is not ok again.

You can try those examples on any market in any timeframe. The result is the same every time.

My conclusion is: The ONCE statement does not work correct. Or did I overlook something? Can anyone provide a clue what went wrong here?

Many thanks in advance for any reply!