On Thread #1041159 Peter post a hold VFP's issue.

Run this on VFP9 return expected THERMO evaluation:

* THERMO calls
* parsing
RECNO=1
* load data
RECNO=2
RECNO=3
RECNO=4
RECNO=8

before (VFP8,7..)

* THERMO calls
* parsing
RECNO=8 && Bug
RECNO=8 && bug
RECNO=1
* load data
RECNO=2
RECNO=3
RECNO=4
RECNO=5 && Bug
RECNO=6 && Bug
RECNO=7 && Bug
RECNO=8

The code:

CLEAR
SET ASSERTS 	OFF
SET CPDIALOG	OFF
SET DEVELOPMENT	OFF
SET COMPATIBLE 	 	FOXPLUS
SET HEADINGS		ON
SET STATUS BAR		OFF
SET NOTIFY		OFF
SET NOTIFY			CURSOR OFF
SET TEXTMERGE		NOSHOW

SET OPTIMIZE		ON

SET ENGINEBEHAVIOR 80

WITH CREATEOBJECT("session")
	SET DATASESSION TO (.datasessionid)	&& default set
	
	SET NULLDISPLAY TO "I'm null"
	CREATE CURSOR myTest (A I NULL)
	INSERT INTO myTest VALUES (5)
	INSERT INTO myTest VALUES (0)
	INSERT INTO myTest VALUES (0)
	INSERT INTO myTest VALUES (null)
	INSERT INTO myTest VALUES (2)	&& VFP don't visit THERMO here
	INSERT INTO myTest VALUES (1)	&& VFP don't visit THERMO here
	INSERT INTO myTest VALUES (7)	&& VFP don't visit THERMO here
	INSERT INTO myTest VALUES (0)

SELECT * FROM myTest;
	WHERE (MOD(A,1000)#0 OR THERMO(A));
	INTO CURSOR rrr

ENDWITH

PROCEDURE THERMO(vValue)
	? "recno()=",RECNO(),"A=",vValue

Of course in the documentation,
nothing of this is brought (at least me I don't find it).

VFPT:
When the way of operating on the data changes,
it Needs to bring it in the documentation.
Is acceptable not to do only it when a bug removes some error produced.