We have one inner net 100Base-T based on Net.ether82557 cards and two outer ethernet based on Net.ether1000 compatible 
cards. Netmap files are the same and full for all computers. Each line works good without bridging, but when we try to 
send file via bridge transmition speed drops drammaticaly down to 100 KB/s. Sometimes speed grows up to full possible 
1024KB/s and sometimes connection breaked. Netinfo helps to get some errors:
Transmittion side (10Base-T): 
      (tx) timeout (no nack)     
      (tx) timeout (no nack)
      (tx) timeout (no nack)
      (tx) got ack/nack for unknown tx
      (tx) got ack/nack for unknown tx
      (tx) got ack/nack for unknown tx
     ...
Reciving side (100Base-T):
     (rx) ok_vseq(): simple dup pkt: pkt type
            rxd dup last pkt, txing ACK
            bad vid seq# - duplicate pkt
     (rx) ok_vseq(): simple dup pkt: pkt type
            rxd dup last pkt, txing ACK
            bad vid seq# - duplicate pkt
   ...
Somtimes rarly error catched:   bad mx validation 
I exclude switching devices faulty - connects all computers with proper cables.
Tried to set priorities for Net.drivers to 25 to exclude Dev influence.
Tried to work with different sets of Net and drivers keys like -h -t and so on.
Tried to set the same full duplex mode for all cards and vice versa.
Tried to use different versions of Net and drivers.
Tried to use different Net.ether1000 compatible cards in relay computer.
Tried to use Net.rtl compatible card in 10Base-T net, connected to ISA cards with key -k.

Scheme of connection :
Net.ether82557 -s10     <->   Net.ether1000 (ISA)    <broute>  Net.ether82557(100Mb)      <-> Net.ether82557(100Mb).
It seems to be common problem with drivers or brouter, when used different type cards on opposite sides.

How can we address this problem?
Best regards!
Konstantin.