There seems to be a bug in apex export about computations that have negated build options.
I have a build option "My build option" and a page computation that uses that build option in a negated way -> "Not My build option". On export and re-import of the app the negation is gone. The computation's build option configuration shows the build option configuration "My build option" (without the not).
Looking into the exported file one can find creation of the computation in the call to wwv_flow_imp_page.create_page_computation. The build option configuration is given in the parameter p_required_patch. The value is the result of wwv_flow_imp.id(...).
wwv_flow_imp_page.create_page_computation(
...
,p_required_patch=>wwv_flow_imp.id(...)
);
With negated build options the value for the parameter p_required_patch usually is a negated value (see the minus before wwv_flow…)
,p_required_patch=>-wwv_flow_imp.id(...)
But unfortunately for page computations that negation gets lost and in the export file the minus is missing.
This applies to the APEX version 23.1 and earlier ones (23.2 not tested yet).