Not saying it's the case here @jcmleng but sometimes organisations, funds and individuals realise that they have a blocking stake, meaning over 10% of the issued shares in a company which can effectively block a takeover attempt by a third party, and they don't want their position to be seen as a blocking stake so they will reduce their position to below 10% because of that.

If you think about it, if you were at company A and were having a look at possible takeover targets, if company B has one or more shareholders with blocking stakes (10% or more each) and company C does not, then company C is going to look like an easier target because there are no major shareholders with blocking stakes who you need to get onside for the takeover to actually happen. So if you're a fundie and you want to make money from an investment (and they usually do) discouraging a takeover of one of your investee companies could be a strategy to employ if you think the company has a long growth runway and you don't want somebody else to come in and snap up the whole company for less than what you think it's going to be worth in the future, but usually fundies are happy enough if a company they hold gets taken over at a premium because it's easy money that they can recycle into another idea.

So it's possible that they only took enough profits to get them below 10% for that reason. Possible but just one possibility.

When companies get to anything over 20% then they become subject to Australian takeover laws, primarily found in Chapter 6 of the Corporations Act 2001 (Cth), which prohibit acquiring voting power of more than 20% in an ASX-listed company unless via specific exceptions like formal takeovers or schemes of arrangement. These laws apply to any acquisition that moves voting power from 20% or below to above 20%, or increases it between 20% and 90%. Once anything over 90% has been achieved then the holder can apply for compulsory acquisition of the remaining shares, which is usually (always?) granted, so that's why anything over 10% blocks that from happening.

There is also what is generally known as Creep Provisions. In Australia, "creep" provisions (specifically, Item 9 of s 611 of the Corporations Act 2001) provide a legal exception to the general prohibition against acquiring more than 20% of a company's voting power. They allow a major shareholder who already holds a substantial stake to gradually increase their control without triggering the requirement to make a formal, company-wide takeover bid. Examples of where this may occur is when the substantial shareholder participates in a dividend reinvestment plan or a capital raising such as an SPP, rights issue or a placement. There are also cases where the substantial shareholder may hold convertible notes or options which, when converted, take them legally over the 20% threshold.

In general you can buy shares on-market up to 20% with the only rule being that whenever your daily trades end up with you owning 5% or more of the company (from below 5% previously) you have to lodge a "Becoming a Sub" notice, and another one (a Change of Subs Holding) every time it moves by 1% or more. Whenever it drops below 5% a "Ceasing...." notice has to be lodged.

A number of organisations have to lodge heaps of these due to their own trading - or the trading of people they hold shares for - keeps taking them above and below 5%. An example is Australia's largest super fund, AustralianSuper, an industry super fund, which allows members to choose to directly invest in any ASX300 companies with up to 80% of their Super balance. Those shares are legally held by the super fund, not the members of the super fund, so it's the fund who has to lodge all the paperwork whenever their own holdings plus all of their members' holdings (within their fund framework) moves above or below 5% or moves by 1% or more between 5% and 20%.

I find it helps to know a little about the way that all works to give some perspective to some of these "Change of..." notices. It can be signalling, or profit-taking, or a sign that the holder is bullish if they are aggressively buying on-market, but it can also be less important and more just a side effect of the way some of these funds operate.