Should you buy the dip in all asset class from your allocation including Bonds?

If you are doing the couch-potato portfolio strategy, and this is part of your rebalancing strategy, then yep.

Else, don't just buy the dips because it's "cheap", because the dip might be caused about by other underlying issue and not due to an undervalue oppotunity. Remember Hyflux?

I note you say "less appealing". Maybe re-evaluate yourself if your risk appetite has changed. If so, then strictly following what you previously planned to follow wouldn't make sense anymore.

All the best. :)

- Jeffrey (jeffreyleezq.com)​​​

At risk of over-simplifying this - I think buying the dip should only be applied to quality assets that you have conviction of. If bonds are just in your porfolio for stability rather than for delivering solid, quality growth, I'm not sure what the utility is in buying more of that.

If however, you're buying more bonds as part of a rebalancing effort or as part of maintaining your asset allocation strategy then it's a different story.

But don't blindly buy the dip, is what I'd do. Not everything "on discount" is worth buying.