To reproduce the issue follow the steps:
1. Create a new scene
2. Create a new UI Input Field
3. Set inputField contentType = InputField.ContentType.Name to check for name validation
4. Play scene
5. Enter the names from the list bellow

Expected -> Current Behaviour
Ewan McGregor -> Ewan Mcgregor
Frans van der Hoff -> Frans Van Der Hoff
Sir Robert Cave-Browne-Cave -> Sir Robert Cavebrownecave
AlisonSt. Clair -> Alison St Clair
Sander van Rossen -> Sander Van Rossen
Leonardo da Vinci -> Leonardo Da Vinci
Martin Luther King Jr. -> Martin Luther King Jr
Desiderio Alberto Arnaz y de Acha III -> Desiderio Alberto Arnaz Y De Acha Iii

Reproduced in 5.3.2f, 5.4.0f1, 5.5.0a5