At some point over night on 30th September (i.e. the night going into 1st October), we saw a number of Spectrum (Charter) customers stop handling fragmented UDP packets. This has manifested itself in such that the phones of affected customers are no longer receiving UDP SIP INVITE packets which exceed whatever their WAN side MTU is. We've so far had 6 customers report the issue - we can see that the last call on 30th September worked and the first and subsequent calls on 1st October failed.
Is anyone aware of an update to CPE devices pushed out that night which may have broken their ability to handle IP fragmentation?