Yup sending an email to support (RIPE) for clarification.

But Twitter NOC is adamant that they are not doing the wrong thing (advertising unallocated address space) because it shows in RADB-GRS via RIPE Whois
On Thu, 12 Jul 2018 at 7:39 pm, Christoffer Hansen <netravnen@gmail.com> wrote:
On Thu, 12 Jul 2018 at 13:28, Christoffer Hansen <netravnen@gmail.com> wrote:
>
> On Thu, 12 Jul 2018 at 12:50, Aftab Siddiqui <aftab.siddiqui@gmail.com> wrote:
> > Thanks for the detailed response and it means if the source is not RIPE then it shouldn’t be considered as authentic data because the resource belongs to RIPE NCC.
>
> That I am not certain about. Normally I would expect to at least find
> an INETNUM object in the RIPE NCC database.

If I go by the list published the RIPE NCC themself.
https://ftp.ripe.net/pub/stats/ripencc/delegated-ripencc-latest
The 188.64.224.0/21 prefix is not allocated at all.

Why Twitter is announcing it. < scratching head for answers >
https://stat.ripe.net/188.64.224.0-188.64.231.255?sourceapp=ripedb#tabId=database

Christoffer