I updated my HDS 10 Gen 2 /w Insight from version 1.1 to 2.1 and now Castaic Lake shows the exact same color as the terrain which makes it look like i am driving my boat on land. The only way to get it to show seperation of the lake is to switch my chart option to 2D.
See screen shots below:
For reference, here is Castaic showed on my Gen 1 unit on the bow which looks fine:

Here is Castaic shown on my Gen 2 unit after the 2.1 update:

Switched the chart option from image shaded relief to 2D, now I can see the lake, but no terrain shading:

Did a hard reset, just for the heck of it. Here is Castaic lake again on 2.1:

Dropped $160 on a Navionics chip, just so I could use my unit again:

Anyone else have this problem too? Zoom into Castaic lake on your Gen 2, what do you see?
There could be problems like this with other lakes too but I haven't check yet.