Have Sliding Panels and Modals always behaved differently for unloading content?

When opening a page include via a Modal, when the modal closes the page include unloads so opening the modal a second time results in a fresh include. When opening a page include via a Sliding Panel, the content doesn’t unload so reopening the panel has a stale include. I expect the behavior of the Modal, and don’t see a reason it would differ, but I don’t have any older environments to test in.

Repro via UI-Only
Page

<skuid__page unsavedchangeswarning="yes" personalizationmode="server" showsidebar="false" showheader="false">
	<models/>
	<components>
		<skuid__text contents="1. Click Open Include in Panel&lt;br /&gt;&#10;2. Close via Close button top right&lt;br /&gt;&#10;3. in console, run skuid.debug.modelMap() and see the model still exists (only 1 possible is on the include)&lt;br /&gt;&#10;4. Click Open Include in Panel again, Panel opens&lt;br /&gt;&#10;ER: Shows form for editing records&lt;br /&gt;&#10;AR: Blank page shows (just close button)&lt;br /&gt;&#10;5. Click Open Include in Modal&lt;br /&gt;&#10;6. Close via Close button top right&lt;br /&gt;&#10;7. in console, run skuid.debug.modelMap() and see the model no longer exists&amp;nbsp;(only 1 possible is on the include)&lt;br /&gt;&#10;8. Click Open Include in Panel again, Panel opens&lt;br /&gt;&#10;AR + ER: Shows form for editing records" uniqueid="sk-3g7o-23891"/>
		<skuid__buttonSet uniqueid="sk-3g6E-9686" position="center">
			<groups>
				<skuid__buttonGroup uniqueId="sk-3g6E-9684">
					<buttons>
						<skuid__button label="Open Include in Panel" uniqueId="sk-3g6E-9685">
							<actions>
								<action type="openSlidingPanel" openbehavior="open">
									<skuid__slidingPanel uniqueid="sk-3g74-13987" size="100%" origin="bottom" behavior="overlay" closeOnPageClick="false">
										<components>
											<skuid__pageInclude includeType="skuid" uniqueid="sk-3g75-14447" pageName="PanelvsModalIssue_Include"/>
										</components>
									</skuid__slidingPanel>
								</action>
							</actions>
						</skuid__button>
					</buttons>
				</skuid__buttonGroup>
				<skuid__buttonGroup uniqueId="sk-3g6G-10652">
					<buttons>
						<skuid__button label="Open Include in Modal" uniqueId="sk-3g6G-10653">
							<actions>
								<action type="showModal">
									<skuid__modal title="New Modal" width="640px" ariaRole="dialog" showHeader="false" showFooter="false" showCloseIcon="false">
										<components>
											<skuid__pageInclude includeType="skuid" uniqueid="sk-3g6z-12107" pageName="PanelvsModalIssue_Include"/>
										</components>
									</skuid__modal>
								</action>
							</actions>
						</skuid__button>
					</buttons>
				</skuid__buttonGroup>
			</groups>
			<styles>
				<spacing/>
			</styles>
		</skuid__buttonSet>
	</components>
	<resources>
		<labels/>
		<javascript/>
		<actionsequences>
			<actionsequence id="0919be0e-d3d8-4c58-aab2-3a1742a6ef4c" label="panel.close" type="event-triggered" event-scope="skuid" event-name="panel.close">
				<description/>
				<actions>
					<action type="closeSlidingPanel" closebehavior="close"/>
				</actions>
			</actionsequence>
			<actionsequence id="97157dd1-3a4f-4645-9e30-dcf15f56eb17" label="modal.close" type="event-triggered" event-scope="skuid" event-name="modal.close">
				<description/>
				<actions>
					<action type="closeModals" closebehavior="close"/>
				</actions>
			</actionsequence>
		</actionsequences>
	</resources>
	<background/>
	<interactions/>
	<surfaces/>
</skuid__page>

Include

<skuid__page unsavedchangeswarning="yes" personalizationmode="server" showsidebar="false" showheader="false">
	<models>
		<model id="CreateRecord" limit="20" query="true" datasource="Ui-Only" createrowifnonefound="true">
			<fields>
				<field id="firstname" displaytype="TEXT" length="255" label="First name"/>
				<field id="lastname" displaytype="TEXT" length="255" label="Last Name"/>
				<field id="age" displaytype="DOUBLE" length="255" label="Age" ogdisplaytype="TEXT" precision="9" scale="0"/>
			</fields>
			<conditions/>
			<actions/>
		</model>
	</models>
	<components>
		<skuid__buttonSet model="CreateRecord" uniqueid="sk-3g6b-17501">
			<groups>
				<skuid__buttonGroup uniqueId="sk-3g6b-17499">
					<buttons>
						<skuid__button label="Close" uniqueId="sk-3g6b-17500">
							<actions>
								<action type="cancel">
									<models>
										<model>CreateRecord</model>
									</models>
								</action>
								<action type="publish" scope="skuid" event="panel.close">
									<params/>
								</action>
								<action type="publish" scope="skuid" event="modal.close">
									<params/>
								</action>
							</actions>
						</skuid__button>
					</buttons>
				</skuid__buttonGroup>
			</groups>
		</skuid__buttonSet>
		<skuid__form showErrorsInline="true" model="CreateRecord" uniqueid="sk-3g6Z-16073" mode="edit">
			<columns>
				<column>
					<sections>
						<section title="New Section" showHeading="false">
							<fields>
								<skuid__field id="firstname" uniqueId="sk-3g6Z-16074"/>
								<skuid__field id="lastname" uniqueId="sk-3g6Z-16075"/>
								<skuid__field id="age" uniqueId="sk-3g6Z-16076"/>
							</fields>
						</section>
					</sections>
				</column>
			</columns>
		</skuid__form>
	</components>
	<resources>
		<labels/>
		<javascript/>
		<actionsequences/>
	</resources>
	<background/>
	<interactions/>
	<surfaces/>
</skuid__page>