SharePoint Online Edit Form JavaScript Errors

Question

I am seeing JavaScript errors on the edit form of one of my tasks lists - see below. I have added my own custom JavaScript on this edit form.

This is in the Chrome browser. I haven't tested sufficiently in IE to know whether they say problem exists, but will be checking over the next couple of days. Regardless, these errors should not occurring in Chrome.

They are intermittent. If I hit F5 to refresh the page they disappear.

This is causing me problems because my custom JavaScript does not run when these errors occur.

What could be causing these errors?

Is there any way to prevent them, or to ensure my custom JavaScript always runs?

EDIT:

This is the JavaScript on the page:

var OPS_TASK_CT_ID = "0x0108003365C4474CAE8C42BCE396314E88E51F00FA61D6E4729D0144BCAE8455B51432E10038383AEC872F6F4E93CAD0A18A8F86C4",
    CHANGE_CONTROL_TASK_CT_ID = "0x0108003365C4474CAE8C42BCE396314E88E51F00391E64F7CAA8794CA403CF082A3CE05B003B7F30E720E93346BD28A966F89FE5FE",
    SECURITY_MANAGER_TASK_CT_ID = "0x0108003365C4474CAE8C42BCE396314E88E51F00B1D7302C0D705E4C8F15D473130B00F000A58ED3A3D435504081A7A23C05A67CD1";

_spBodyOnLoadFunctionNames.push("Init");

function Init(){
    // Check what content type this form is
    var ctVal = $("select[title='Content Type']").val();

    if (ctVal == OPS_TASK_CT_ID) {
        var fieldsToMakeReadOnly = [
            { title: "Server Name", type: "input" },
            { title: "Server ID", type: "input" },
            { title: "Server Location", type: "select" },
            { title: "Server Type", type: "select" },
            { title: "OS", type: "select" },
            { title: "Classification", type: "select" },
            { title: "Service ID", type: "input" },
            { title: "Recovery Documentation", type: "input" },
            { title: "Supported By SSC", type: "input" },
            { title: "Consistency Group", type: "input" },
            { title: "Change Reference Number", type: "input" },
            { title: "Decommissioned", type: "input" },
            { title: "Recovery Order", type: "input" }
        ];

        w_FixTaskEditForm();
        w_MakeFieldsReadonly(fieldsToMakeReadOnly);     
    }
    else if (ctVal == CHANGE_CONTROL_TASK_CT_ID) {
        w_FixTaskEditForm();
    }
    else if (ctVal == SECURITY_MANAGER_TASK_CT_ID) {
        w_FixTaskEditForm();
    }
}

These are the functions being called (in another JS file):

function w_MakeFieldsReadonly(fields) {
    var title;
    var type;

    for (var i = 0; i < fields.length; i++) {
        title = fields[i].title;
        type = fields[i].type;

        $(type + "[title='" + title + "']").attr("disabled", true);
    }
}

function w_FixTaskEditForm() {
    var title;
    var type;
    var fields = [
            { title: "Content Type", type: "select" },
            { title: "Task Name", type: "input" },
            { title: "Start Date", type: "input" },
            { title: "Due Date", type: "input" },
            { title: "Assigned To", type: "input" },
            { title: "% Complete", type: "input" },
            { title: "Predecessors possible values", type: "select" },
            { title: "Priority", type: "select" },
            { title: "Task Status", type: "select" }
    ];
    for (var i = 0; i < fields.length; i++) {
        title = fields[i].title;
        type = fields[i].type;

        $(type + "[title='" + title + "']").first().closest("td[class='ms-formbody']").parent().hide();
    }

    // Make the task description field read only
    $("[id^='Body_'][id$='_$TextField_inplacerte']").attr("contenteditable", "false");

    // Show the rest of the fields in the form (likely custom fields)
    if (typeof rlfiShowMore === "function") {
        rlfiShowMore()
    }
}