Why is the route name included in the query?

Question

I really can't get my head around this problem. I have a temporary fix which is totally moving the route.

Here are the models in question

Activity.belongsToMany(User, {through: "activity_completion", as: "member"});

User.belongsToMany(Activity, {through: "activity_completion", as: "member"});

The association works, I have appropriate unit test.

This is the faulty code

router.get("/subscriptions", auth, async (req, res) => {

try {
    await db.sequelize.sync();


    const listOfActivities = await Activity.findAll({
        include: {
            model: User, as: 'member',
            attributes: ['firstName', 'lastName', 'role'],
        },
        where: { expertId: req.decoded.userId },
    });
    res.json({ "data": listOfActivities });


} catch (e) {
    res.json({ "error": e.message });
}

})

This works fine ONLY if I move the code to another route. In the current route, it always gives me this error on query

ERROR: INVALID INPUT SYNTAX FOR TYPE INTEGER "subscriptions"

In any case, the damn sequelize tries to find an Activity which has "subscriptions" as the id

db-1 2022-05-16 14:50:33.602 UTC (40) ERROR: invalid input syntax for type integer: "enrollment" at character 259

db-1  2022-05-16 14:50:33.602 UTC [40] STATEMENT: SELECT ..(misc).. FROM "activities" AS "Activity" WHERE ("Activity"."id" = 'subscriptions' )

Note that if I change the route name, for example as "enrollments"

db-1  2022-05-16 14:50:33.602 UTC [40] STATEMENT: SELECT ..(misc).. FROM "activities" AS "Activity" WHERE ("Activity"."id" = 'enrollments' )

And note that once I changed the route, it works fine. I moved it from IP/activities/enrollments to IP/enrollments and it works perfectly.

Do you have any idea what this could be? Thanks in advance everyone