Invalid date when timeOnly defined on datetime UIComponent

[duckchip]

Preconditions (*)

1. Magento 2.3.1

Steps to reproduce (*)

1. Define a ui_component form.xml
2. add a Datetime UI component with the option 'timeOnly' set to 'yes'

<field name="start_time"]
    [argument name="data" xsi:type="array"]
        [item name="config" xsi:type="array"]
            [item name="dataType" xsi:type="string"]string[/item]
            [item name="label" xsi:type="string" translate="true"]Start Time[/item]
            [item name="formElement" xsi:type="string"]date[/item]
            [item name="source" xsi:type="string"]import_profile[/item]
            [item name="dataScope" xsi:type="string"]start_time[/item]
            [item name="options" xsi:type="array"]
                [item name="timeOnlyTitle" xsi:type="string"]Select Start Time[/item]
                [item name="showsTime" xsi:type="boolean"]true[/item]
                [item name="timeOnly" xsi:type="boolean"]true[/item]
                [item name="timeFormat" xsi:type="string"]HH:mm:ss[/item]
                [item name="dateFormat" xsi:type="string"]yyyy-MM-dd[/item]
            [/item]
        [/item]
    [/argument]
[/field>
{code}
1. Save the form and check the result. 

### Expected result (*)
1. Correct time value

### Actual result (*)
1. The value states: 'Invalid Date'

### Additional information
This problem doesn't occur when the option 'timeOnly' is not defined. 

My best guess is that the problem happens inside the /module-ui/view/base/web/js/form/element/date.js at 'onShiftedValueChange' function..

{code}
 /**
        * Prepares and sets date/time value that will be sent
        * to the server.
        * * @param {String} shiftedValue
         */
        onShiftedValueChange: function (shiftedValue) {
            var value,
                formattedValue,
                momentValue;

            if (shiftedValue) {
                momentValue = moment(shiftedValue, this.pickerDateTimeFormat);

                if (this.options.showsTime) {
                    formattedValue = moment(momentValue).format(this.timezoneFormat);
                    //formattedValue returns an incorrect value. 
                    value = moment.tz(formattedValue, this.storeTimeZone).tz('UTC').toISOString();
                } else {
                    value = momentValue.format(this.outputDateFormat);
                }
            } else {
                value = '';
            }

            if (value !== this.value()) {
                this.value(value);
            }
        },

[m2-assistant]

Hi @duckchip. Thank you for your report.
To help us process this issue please make sure that you provided the following information:

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• Information on your environment
• Steps to reproduce
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@duckchip do you confirm that you were able to reproduce the issue on vanilla Magento instance following steps to reproduce?

• yes
• no

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[m2-assistant]

Hi @shikhamis11. Thank you for working on this issue.
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[magento-engcom-team]

✅ Confirmed by @shikhamis11
Thank you for verifying the issue. Based on the provided information internal tickets MC-17293, MC-17294 were created

Issue Available: @shikhamis11, You will be automatically unassigned. Contributors/Maintainers can claim this issue to continue. To reclaim and continue work, reassign the ticket to yourself.

[konarshankar07]

@duckchip
Can you please give more information like which type of column did you created in the table?

Thanks

[duckchip]

@konarshankar07 This is not on the table/listing but on the form UI component.

[konarshankar07]

@duckchip Can you please add a screenshot of the error message?