Packetloss/Dropped packets on OpenWrt device

[Knogle]

Hey friends how are you doing.
A few days ago i was wondering about my new board i have purchased, an X10SBA having issues with dropped packets every time.

Bonding + X10SBA-F almost dropping every packet

Hey friends how are you doing. I've build up a new router for my 1Gbps connection and i still had an unused X10SBA lying around. So i wanted to use this board, because it's really nice, due to it's dual NIC, perfect for bonding. So that's what i've done, i have compiled OpenWrt almost with default settings, only added bonding and LuCi support. Unfortunately i have a quite strange behaviour. After establishing the LAG on the device it doesn't respond correctly anymore to any kind of network …

Now i have tried different x86 devices with OpenWrt and i am experiencing an interesting phenomenon.
When pinging my OpenWrt device inside the network i am experiencing a packetloss of around 3%, sometimes more, sometimes less. It starts suddenly, and disappears.
What might be the issue? Or what's the best way to troubleshoot?
What's the reason for "dropped" packages? Are they faulty?
I think the issue is somehow related to my switched infrastructure and not the OpenWrt device itself.
Does someone have any advice in order to find the issue behind this?
This setup has worked like this for a few years, but now during the last weeks i am experiencing issues.

These both interfaces are bonded.

eth0      Link encap:Ethernet  HWaddr 00:25:90:7F:6C:AB  
          UP BROADCAST RUNNING SLAVE MULTICAST  MTU:1500  Metric:1
          RX packets:47698152 errors:0 dropped:21508 overruns:0 frame:0
          TX packets:15661880 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:29566914769 (27.5 GiB)  TX bytes:6232184616 (5.8 GiB)
          Interrupt:20 Memory:dfb00000-dfb20000 

eth1      Link encap:Ethernet  HWaddr 00:25:90:7F:6C:AB  
          UP BROADCAST RUNNING SLAVE MULTICAST  MTU:1500  Metric:1
          RX packets:25077445 errors:42 dropped:24 overruns:0 frame:1
          TX packets:56707046 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:18923851046 (17.6 GiB)  TX bytes:42015491751 (39.1 GiB)
          Interrupt:16 Memory:df900000-df920000 

WAN facing VLAN on the bonding interface

bonding-i0.2100 Link encap:Ethernet  HWaddr 00:25:90:7F:6C:AB  
          inet addr:192.168.178.39  Bcast:192.168.178.255  Mask:255.255.255.0
          inet6 addr: fe80::225:90ff:fe7f:6cab/64 Scope:Link
          inet6 addr: 2a02:908:230:5280:225:90ff:fe7f:6cab/128 Scope:Global
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:6647132 errors:0 dropped:64034 overruns:0 frame:0
          TX packets:3694254 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:8334946903 (7.7 GiB)  TX bytes:507536812 (484.0 MiB)

LAN facing interface on the bonding interface

bonding-i0 Link encap:Ethernet  HWaddr 00:25:90:7F:6C:AB  
          inet addr:192.168.3.1  Bcast:192.168.3.255  Mask:255.255.255.0
          inet6 addr: fe80::225:90ff:fe7f:6cab/64 Scope:Link
          inet6 addr: 2a02:908:230:5293::1/64 Scope:Global
          inet6 addr: fdfb:9584:eb33:3::1/64 Scope:Global
          UP BROADCAST RUNNING MASTER MULTICAST  MTU:1500  Metric:1
          RX packets:72775596 errors:42 dropped:29966 overruns:0 frame:1
          TX packets:72368925 errors:0 dropped:42 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:48490764624 (45.1 GiB)  TX bytes:48247675180 (44.9 GiB)

br-Perf is directly connected to the 10G interface of my computer through fiber, no issues here.

 Link encap:Ethernet  HWaddr 00:02:C9:06:A5:26  
          inet addr:192.168.7.1  Bcast:192.168.7.255  Mask:255.255.255.0
          inet6 addr: fe80::202:c9ff:fe06:a526/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:24503 errors:0 dropped:0 overruns:0 frame:0
          TX packets:27213 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:1687381 (1.6 MiB)  TX bytes:5591745 (5.3 MiB)