Plain HTML elements displaying alongside Materialize rendered ones

The main issue here is as follows: I am developing a website with JSP files, and materialize as a framework for visual components. When using different elements from them, they work all right, but alongside them come the plain HTML elements (examples described below). I would like to understand why this may be happening, both .js and .css libraries are declared in the JSP files, but the problem persists.

Example #1: HTML checkbox displaying alongside the Materialize one.

The code used is as follows: login.jsp

<div class="col s12" style="align-content: center;">
   <label>
      <input type="checkbox" name="remember-me">
        <span><spring:message code="loginpage.rememberme"/></span>
   </label>
</div>

Example #2: List items displaying first as the materialize dropdown (correctly) and right after the HTML list with the elements (incorrectly).

Image #1: List incorrectly displayed

Image #2: List displays and unfolds correctly (notice how the checkbox problem persists along all views)

Code of createProduct.jsp:

<div class="input-field">
   <form:label path="ecotag">
      <spring:message code="createproduct.form.taglist"/>
   </form:label>
   <form:select path="ecotag" multiple="true">
      <c:forEach items="${tagList}" var="ecotag">
         <form:option value="${ecotag.id}">
            <c:out value="${ecotag.tag}"/>
         </form:option>
      </c:forEach>
   </form:select>
   <form:errors path="ecotag" element="p" cssClass="error"/>
</div>

Thank you for reading.