Consider fields G1 and G2 being computed fields with inverse methods that
require the value of a common dependency F, which is also a computed field.
For inversing G1 and G2, their values are put in cache, then their inverse
method is called. If the inverse method of G1 requires the computation of F,
setting F's value will invalidate both G1 and G2 in cache. Hence the value of
G2 is lost when invoking its inverse method!
The fix consists in marking G1 and G2 as being computed before invoking their
inverse method, which prevents them from being invalidated by field F.
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