Given that almost all of StashAway's portfolios crashed beyond the SRI (1% probability of occurence) during the recent crash, are there any measure that will be taken to prevent same situation ?

StashAway put up a summary on this. Can read below:
http://lnk.stashaway.com/u/gm.php?prm=ZH5awSBT9...

The 1% you're highlighting is occurrence above the 3rd standard deviation from mean. If markets didn't recover and tanked further we would be looking at a black swan event. An anomaly.

But on to your planning.

If you have short term goals like a wedding and a house, then you're using your robo advisor wrongly.

Segment your investment objectives. Long term monies should be kept separate from short term money.

You can only take significant risk on money not required for at least 10-30 years, but pretty much no risk whatsoever on money needed within 3 years.

It's not your robo advisors fault, they're just doing what you tell them to do. It was your mistake to lump both goals together on a higher risk portfolio.

Each objective needs different attention and risk allocation due to differing time horizons and requirements for immediate liquidity.