I am an non native English speaker in where the some pronunciations taught have been obsolete in British English . Recently, I've got some time to do my research and discovered something called yod-coalescence.
Yod-coalescence sometimes occurs with clusters, like /dj/ and /tj/ which coalesce into /dʒ/ and /tʃ/ respectively.
For example, during would be pronounced as /dʒʊərɪŋ/ instead of /djʊərɪŋ/, and Tuesday would be pronounced as /tʃuːzdeɪ/ instead of /tjuːzdeɪ/.
How common is it in modern RP?