It's very surprising news, who would expect Lightning Network protocol and client which are on development phase have security issue which could cause loss of funds 
Lol 
The fact that the loss of funds "could happen" but hasn't happened yet is more surprising
And AFAIK such cases which happened because scenario we know already such as :
1. being offline and another party broadcast earlier state of the channel
2. we attempt to broadcast earlier state of the channel and another party broadcast "punishment" transaction
how many idiots claim LN will solve Bitcoin scaling problems
Only idiot claim LN will solve Bitcoin scaling problem, everyone who've tried LN or learn how it works knows it only partially solve the problem (specifically micro-transaction for user who often make transaction).
Over 2 years for segwit and LN still can't get out of beta mode. (Lame)
SegWit "beta mode" already ended the moment it's activated on 2017. The "beta mode" happened on SegNet (testnet for SegWit) about 3-4 years ago.