The declarative process model described contains a number of constraints that are used to define different aspects of the business processes, such as existence, absence, exactly one execution, initialization, response, precedence and succession. However, there are some anomalies present in this model which could be potentially problematic or challenging for stakeholders.

One anomaly is the use of non-coexistence constraint 'Non Co-Existence: given a couple of activities (A, B), if A occurs then B should not occur'. This type of constraint could lead to unexpected behaviors in the business process, since it forces every time an activity happens, another one cannot also be executed.

Another anomaly is the presence of non-succession and non-chain succession constraints. These types of constraints can cause issues when designing a system that relies on these relationships between activities (successor and predecessor), since they imply that certain activities will not occur in a sequence or chain within the model, but it's possible for some other activity to happen in its place.

Moreover, it could be problematic if there are no responses, precedence or succession constraints. This is because it would lead to a situation where all events will execute their defined behavior without any guidance from other activities (e.g., all 'Request Payment' must happen first, etc.).

Also the definition of alternate response and alternate precedence does not appear in the model, but could be an important aspect when dealing with uncertainty or non-fully deterministic behavior of processes.

In conclusion, these constraints should be reviewed for their ability to define the system's expected behavior as accurately as possible. For instance, additional responses, precedence and succession constraints could help manage situations that are not well defined in the model, while ensuring that all required events will happen in a consistent manner within the business process.