Selection Vs Aggregation Conundrum

Dear APO Rock Stars,

Here is a nagging one.

Selection ID in a Background job

CHAR1 =  A

CHAR2 =  B

CHAR3 = *

CHAR4 NE C (not equal C)

CHAR7 = D

Aggregation level

CHAR1

CHAR2

CHAR3

CHAR5

CHAR6

I use this to generate some bogus Alert (DB Alert from a macro). The alert profile does NOT have any selection ID.

1) Alert gets generated but cannot be loaded to SDP94.. message "selection cannot be chosen"

What is happening ? I am close to completing a PhD on this but cannot make out.

2) Hint: I removed CHAR7 = D from selection ID and I am  able to load the Alert selection to SDP94 from Alert monitor

What is happening ?

Thanks

Lok