data function in computed turns into POJO `{_r_unbound: func}`

[ppena-LiveData]

If a function is defined in Ractive data, and that function is called via a computed, then calling ractive.get() will incorrectly have a plain-old-javascript-object, like {_r_unbound: func}, for that function's keypath, when it should have the function (bound to the Ractive). I found it because I had one Ractive linked to another, and the template of the second Ractive got multiple things from the first Ractive, like this:

<script src="https://cdn.jsdelivr.net/npm/ractive"></script>
<div id="target"></div>
<script>
    const ractiveSource = Ractive({
        data: {
            testFunc: function (val) {
                // not called via a computed, so ractiveDest won't have a problem using it
                return `"testFunc: val=${val}"`;
            },
            testFuncInComputed: function (val) {
                return `"testFuncInComputed: val=${val}"`;
            }
        },
        computed: {
            computedVal: function () {
                this.get('testFuncInComputed')('sourceTestVal');
            }
        }
    });
    const ractiveDest = Ractive({
        target: '#target',
        template: `
            testFunc(...)={{ractiveSource.testFunc("func call works")}}
            testFuncInComputed(...)={{ractiveSource.testFuncInComputed("func call does not work")}}`,
        data: {},
        onconfig: function () {
            this.link('', 'ractiveSource', {ractive: ractiveSource});
        }
    });
</script>

But a much simpler reproduction is just to call .get() more than once:

<script src="https://cdn.jsdelivr.net/npm/ractive"></script>
<div id="target"></div>
<script>
    const ractiveSource = Ractive({
        data: {
            testFuncInComputed: function (val) {
                return `"testFuncInComputed: val=${val}"`;
            }
        },
        computed: {
            computedVal: function () {
                this.get('testFuncInComputed')('sourceTestVal');
            }
        }
    });
    // this get() will call computedVal(), and "testFuncInComputed" will get added to childByKey
    const result1 = ractiveSource.get();
    console.log(result1.testFuncInComputed('yay'));
    // this get() will now call child.getVirtual(), which converts the bound func to just a POJO: {_r_unbound: func}
    const result2 = ractiveSource.get();
    console.log(result2.testFuncInComputed('sob'));
</script>