Many academics in the UK believe that the workload allocation models applied in many universities are broken and do not reflect the true time required to perform academic duties, forcing staff to work evenings and weekends to stay on top of their marking and preparation of lectures. This is one of four fights in a dispute between the Universities UK (representing employers) and the University and College Union (representing staff). The dispute has been ongoing for several years now and has resulted in quite a few strikes and actions short of striking, such as assessment boycotts, etc.
In some universities in the UK where I worked, the amount of time allocated to create teaching materials was about 2 hours of preparation per 1 contact hour of teaching. Modules typically have ~30 contact hours, so you get 60 hours (1.5 weeks) to prepare everything for your students. This includes typeset lecture notes, problem sheets and answers to them, mock exam questions and fully worked out solutions. Everything needs to be provided via some online system, and departments usually monitor the quality of teaching materials. Unlike in some EU countries, in the UK students typically expect learning materials to be provided to enable them to learn even without attending some (or all) of the classes. You can deliver a blackboard lecture, but you will be asked to provide typeset lecture notes afterwards.
For me, personally, it usually takes about 3 months to prepare the first draft of the materials which I am not completely ashamed of.
The inadequate workload allocation models put a very severe pressure on academic staff. Some better departments manage it by giving the same modules to the same academics for several years in a row, making it possible to maintain and improve materials little by little. Some less organised departments suffer from high staff turnover and (re)allocate modules at the last moment each year, as you described in your question. In this case academics have no motivation to put extra time to prepare good materials, because next year they may be given a completely new module again. Students complain, managers react by putting more pressure on staff, academics burn out and leave, turnover increases and the process spirals down.
Is this normal?
Disorganised departments and poor admin practices in academia are not normal, but also not uncommon in the UK, as evidenced by the UCU dispute ongoing for several years all across the UK.
Are all universities like this?
No, there are still quite a few good ones. The marketization of higher education in the UK continues though.
Shouldn't professors refuse to accept a module if they haven't been given a sufficient amount of time to prepare?
Some may try to cause trouble, but this is not going to be popular with their Heads of Departments. However, academics can't refuse to teach a module or to take an admin role if it is within their "capacity" as per the workload model approved for use in their Department / University. Needless to say, the people who approve this model are mostly administrators and managers, not common professors and lecturers. Many professors do not agree with the workload model approved by admin/managers in their University, as evidenced by the ongoing national dispute.