I'm still seeing this issue on the 4.15.0-39-generic kernel:

[467738.375137] e1000 0000:05:01.0 enp5s1f0: Detected Tx Unit Hang
                  Tx Queue             <0>
                  TDH                  <44>
                  TDT                  <44>
                  next_to_use          <44>
                  next_to_clean        <25>
                buffer_info[next_to_clean]
                  time_stamp           <106f70e55>
                  next_to_watch        <26>
                  jiffies              <106f70ff8>
                  next_to_watch.status <0>
[467740.391180] e1000 0000:05:01.0 enp5s1f0: Detected Tx Unit Hang
                  Tx Queue             <0>
                  TDH                  <44>
                  TDT                  <44>
                  next_to_use          <44>
                  next_to_clean        <25>
                buffer_info[next_to_clean]
                  time_stamp           <106f70e55>
                  next_to_watch        <26>
                  jiffies              <106f711f0>
                  next_to_watch.status <0>
[467742.407313] e1000 0000:05:01.0 enp5s1f0: Detected Tx Unit Hang
                  Tx Queue             <0>
                  TDH                  <44>
                  TDT                  <44>
                  next_to_use          <44>
                  next_to_clean        <25>
                buffer_info[next_to_clean]
                  time_stamp           <106f70e55>
                  next_to_watch        <26>
                  jiffies              <106f713e8>
                  next_to_watch.status <0>
[467744.423373] e1000 0000:05:01.0 enp5s1f0: Detected Tx Unit Hang
                  Tx Queue             <0>
                  TDH                  <44>
                  TDT                  <44>
                  next_to_use          <44>
                  next_to_clean        <25>
                buffer_info[next_to_clean]
                  time_stamp           <106f70e55>
                  next_to_watch        <26>
                  jiffies              <106f715e0>
                  next_to_watch.status <0>
[467745.319133] e1000 0000:05:01.0 enp5s1f0: Reset adapter

05:01.0 Ethernet controller: Intel Corporation 82546EB Gigabit Ethernet Controller (Copper) (rev 03)
	Subsystem: Intel Corporation PRO/1000 MT Dual Port Server Adapter
	Flags: bus master, 66MHz, medium devsel, latency 32, IRQ 16
	Memory at f7220000 (64-bit, non-prefetchable) [size=128K]
	Memory at f71c0000 (64-bit, non-prefetchable) [size=256K]
	I/O ports at d040 [size=64]
	Expansion ROM at f7180000 [disabled] [size=256K]
	Capabilities: [dc] Power Management version 2
	Capabilities: [e4] PCI-X non-bridge device
	Capabilities: [f0] MSI: Enable- Count=1/1 Maskable- 64bit+
	Kernel driver in use: e1000
	Kernel modules: e1000

05:01.1 Ethernet controller: Intel Corporation 82546EB Gigabit Ethernet Controller (Copper) (rev 03)
	Subsystem: Intel Corporation PRO/1000 MT Dual Port Server Adapter
	Flags: bus master, 66MHz, medium devsel, latency 32, IRQ 17
	Memory at f7200000 (64-bit, non-prefetchable) [size=128K]
	Memory at f7140000 (64-bit, non-prefetchable) [size=256K]
	I/O ports at d000 [size=64]
	Expansion ROM at f7100000 [disabled] [size=256K]
	Capabilities: [dc] Power Management version 2
	Capabilities: [e4] PCI-X non-bridge device
	Capabilities: [f0] MSI: Enable- Count=1/1 Maskable- 64bit+
	Kernel driver in use: e1000
	Kernel modules: e1000


This is a dual-port adapter, but I also saw the issue with the on-board i217 chip too.