There is some kind of SR buff applied in some cases:
In recent streamer’s Tesla Bronze to Silver challenge with Moira, he gets clear SR buff up to 95. Here is the list of SR gain/loss:
Bronze (slightly after first placement matches on new account):
+35 +39 45 +48 +59 +64 +82 +78 +79
Silver:
+93 (tenth win in a row)
-15 -13
+32 +33 +30 +32 +40
-16
+30 +27
-16
+33 +34 +30 +32 +40 +40 +50
Gold:
+45 +60 +73 +90 +88 +95
Plat:
+88 +88 +84 +79 +78
-23 -23
+27
-23
+25 +25 +25 +25 (SR gain seems to be blocked already even though Diamond is not fully reached)
+28 (played in duo with a lower SR average)
-24 (same as above even though Tesla individual rank was Diamond with 3002)
Is it just applied for a certain number of competitive games with a new account or on any account? That has to be checked. It makes sense to reward someone drastic increase in skills if coming after a long break of training for example. It wouldn’t otherwise because it would facilitate boosters’ jobs.
In Tesla’s case, there seems to be a difference between the first 10 games studied (that are not exactly the first 10 after initial placement matches, since he has already 3 hours of play and 14 wins on his profile) and after the first two losses. After the losses what I think is more than 30 games after the first placement match, the SR gain is around between 30-33 for 4 games before increasing to 40 on the fifth. Same thing happens later in a 18 wins streak: the first 4 have a similar SR around 32, the next 4 are between 40 to 50 and then it increases again to a new plateau, wider, that goes from 78 to 95.