It's been a default line profile of Interleaving on Huawei cabinets since at least August 2015
Downstream
Initially, low interleaving is enabled by default on all retransmission lines. Once DLM has positively identified that the modem supports retransmission then retransmission is enabled. This happens after a few days. If the low level of retransmission is not good enough to correct all errors then the high level is selected by DLM. If the line remains unstable and cannot be adequately managed by DLM with retransmission profile then Interleaving is applied as normal.
The recent change more affected ECI lines, and some Huawei new provisions that sometimes started on fastpath.
I migrated from BT to Plusnet a couple weeks ago. The line dropped from 44Mb (3db, retx low) to 31Mb (low interleaving/INP=3).
Within 8 days I was back to 3dB / G.INP
BT
14/10/18 3dB, G.INP(retx low), sync = 44330
Plusnet (migration 15/10/18)
15/10/18 6dB, Interleaving Low, sync = 31165
17/10/18 6dB, G.INP (retx low) sync =36251
19/10/18 5dB, G.INP (retx high), sync = 38275
21/10/18 4dB, G.INP (retx high), sync = 40523
23/10/18 3dB, G.INP (retx high), sync = 44224
Capped the line about 1 min as I remembered I was still retx high. should be low again in a few days!