A SVI/blind child entitles a claimant to the disabled child element, but does not exempt them, from the benefit cap?

Bit of a rhetorical question really, but -
is it not an anomaly that if you have a child who is blind or severely visually impaired, you are entitled to the disabled child element in UC, but this does not exempt you from the benefit cap unless you also have DLA in payment?

I have a client who successfully got the disabled child element in her UC, was in temp accommodation and so was not aware of the benefit cap until moving into a tenancy in October when UC HCE was in place and cut her income by 25%. She did not claim DLA until she was referred in to our service for advice in late Feb.

I think we would normally encounter clients who do it the other way, so, are identified as having a disabled child and apply for DLA, then find out they can get the disabled child element, rather than the other way round ... We have of course applied for DLA (15 weeks time estimate for a decision!) and this will be automatically awarded at HRM, and for this child probably MRC also. But the removal of the benefit cap will only go back to the start of DLA and leave a 3-month period where she was heavily capped. DHP team are assisting because she is post NOSP and LL wants to refer to court.

Just seems to me a bit of an anomaly? Especially as such a a child would have an automatic entitlement to DLA, it seems that the law is written in such as way as to not make this kind of household exempt from the cap.